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The announcement is made in the dining car over breakfast, when everyone has been gathered for long enough to notice the glaring absence of Seoul’s most respected detective. Renjun is startled from his thoughts by the slam of the compartment door, train conductor marching briskly in with Jisung at his heels. It’s Jisung who gives it away—face pale against the purple collar of his uniform, trembling from head to toe like he’s seen a ghost. Renjun knows what the conductor is going to say before he opens his mouth.

“A passenger has been found dead in his room.”

The carriage falls silent, save for the clink of metal as people set down their cutlery. Renjun swallows, tries to blink away the image of Mark’s earnest smile imprinted onto the back of his eyelids. At the next table, Donghyuck’s expression is dark. Chenle is sitting two tables away with his back to them; the line of his shoulders grows tense as the conductor explains how Jisung had discovered Mark’s body, fatal stab wound to the stomach.

Without Mark, it goes unspoken that any chances of solving the mystery are slim. It’s Jeno who voices the other thought on everyone’s mind.

“If this happened last night, then the killer is on board the train right now. There are still eight hours until we arrive at our destination. Who’s to say the killer won’t strike again?”

A collective murmur arises, anxious looks exchanged between passengers. Renjun can’t afford to panic—he’d known that embarking on this journey would carry such a risk, yet he’d chosen to do it anyway. His breath leaves him in a shaky exhale, hand reaching unconsciously for Jaemin’s under the table.

In the seat next to him, Jaemin’s expression is stoic. He’d always been the better of them at keeping his cool. His palm is warm as he gives Renjun’s hand a soft squeeze, gaze flickering across the occupants of the carriage. Eventually, they return to rest on Renjun.

Don’t worry, Jaemin’s eyes say. I won’t let anything happen to you.

Mark Lee is possibly the nicest person Renjun has ever met.

Renjun thinks this to himself as he follows several steps behind Mark down the long corridor of the sleeping car, two sets of luggages in Mark’s arms. When Renjun had collided with him in the entrance carriage as they boarded the train, causing Mark’s suitcase to burst open on the ground and sending papers flying everywhere, Renjun’s first thought was that Mark must be a scholar. But then Mark had introduced himself with a sheepish smile that seemed strangely familiar, offering to help Renjun with his oversized luggage, and Renjun had been too flustered to pursue the thought further.

If Mark is a scholar, he’s a very strong one. Renjun stares at the broad expanse of his back as Mark walks in front of him, trying to reconcile how effortlessly Mark lifts the bags with the cashmere sweater vest he’s wearing and thick-framed glasses perched on his nose. So preoccupied is he by these thoughts that Renjun forgets to feel embarrassed that another man is carrying his luggage for him, and almost crashes head-first into Mark (again) when Mark stops walking abruptly in the middle of the corridor.

“Compartment two, you said?” Mark sets Renjun’s luggage down on the carpet, turning to him with a smile. “Here we are. Sorry again for bumping into you earlier.”

“Not at all,” Renjun answers faintly. The collision had clearly been Renjun’s fault, and Mark had clearly been the one inconvenienced. “Thank you for helping me. You didn’t have to.”

“But I wanted to,” Mark says with such sincerity that Renjun is momentarily taken aback. “We’re in for a long ride,” Mark continues. “So it’ll be nice to get to know everyone a little. I have a long job waiting for me in Beijing—not that there’s anything bad about being employed, but, you know. I want to make the best of this trip, I guess.” He blushes, as if winded by his own speech. “Anyway. What brings you here?”

“I have family near Beijing,” Renjun says, trying not to look too amused.

Mark nods, eyes wide. “That’s nice. Really nice. Not many people leaving Seoul by train these days, are there? Not since—” He hesitates, clears his throat. “Well, I’ll leave you to get settled in. Do you, maybe, want to get a drink with me later?”

The look on his face is endearingly hopeful. Renjun blinks, surprised, and Mark seems to lose his nerve almost instantly, putting up a hand to cut Renjun off before he can respond. “Think about it, okay?” he says, and then with a shy smile he turns abruptly to leave, single set of luggages in hand as he continues down the corridor.

As soon as Mark disappears into the compartment at the end of the carriage, the door Renjun is standing in front of slides open with a click, a familiar head popping out from behind it.

“Renjun,” Jaemin greets with a lazy smile. “I didn’t know you liked good boys. Are you going to get a drink with him later?”

Renjun feels himself flush. “I don’t know. Should I? He’s nice, but there’s something about him... I feel like I’ve seen him somewhere before.”

“You have,” Jaemin says. “He’s—”

They’re interrupted by a loud clatter as the carriage door in the direction Renjun had just come from is pulled open with more force than perhaps necessary, someone stepping hastily into the cabin. He appears well-dressed, keen eyes darting around the carriage before they come to rest on Renjun and Jaemin.

“Have you seen Mark?” he asks. “About my height, wears glasses? Cute face?”

“Nope,” Jaemin says.

The stranger huffs out a breath, blowing strands of brown hair out of his face in the process. “I could’ve sworn I saw him come this way.” After a pause he seems to notice them as if for the first time, straightening abruptly with no trace of the frown that had decorated his face seconds earlier. “Where are my manners?” He extends his hand with a smile that can only be described as dazzling. “Lee Donghyuck. Cars are my trade, and I’m headed to Beijing on business. What brings the two of you aboard the infamous Haerang?”

“Na Jaemin,” Jaemin introduces, not taking his hand. “Engineer.”

“Huang Renjun,” Renjun accepts the handshake, noting the unique weave of Donghyuck’s suit around the sleeve. “Clothes… are my trade. We’re here for business too. Mostly.”

“Clothes.” Curiosity is alight in Donghyuck’s eyes as he cocks his head. “Fashion design?”

“Tailoring.”

Donghyuck hums, eyes moving between them. Renjun gets the feeling they’re being assessed. “I suppose there’s no point in avoiding the elephant in the room,” Donghyuck’s tone is conversational. “Five murders on the Haerang Rail in the last couple of months. An interesting time for a trip. The police would have us believe there’s no need to worry, since they’ve arrested the killer in every case, but…”

“But it keeps happening,” Renjun finishes for him. “So people believe the real killer must still be out there.”

Donghyuck’s smile is wry. “You don’t look half as nervous as some of the other passengers I’ve seen. Seasoned travelers?”

Apprehension sits high in Renjun’s chest, where it had made a home for itself since the moment he’d set eyes on the train’s sleek blue exterior. Barely a year in operation and Haerang’s first Seoul-Beijing express train has been plagued by misfortune on an unprecedented scale. It feels almost reckless to be on board so soon after the last murder had made the news.

Jaemin looks like he’s trying not to roll his eyes. “You don’t look nervous yourself.”

“You’re right—I’m not,” Donghyuck says airily. “I have Mark. You know who he is, of course.”

“Seoul’s best private detective,” Jaemin answers, without missing a beat. Renjun almost drops the bag he’s still holding. That’s why Mark had seemed so familiar. That’s why he had those papers. Even if he didn’t recognize his name, Renjun should have recognized his face—the very same plastered across every headline when Mark had solved that kidnapping case involving a Minister’s young daughter last year. Renjun tries to shake himself out of his daze at the implication. The Mark Lee is on board the train with them.

“Are you acquainted with him?” Jaemin asks.

“No,” Donghyuck says. “But I will be.” He pulls up the sleeve of his suit and checks his watch with a sigh. “Not long now until we depart. Maybe Mark found his way to the lounge? I heard the bar on board is better than the ones in the city.” He turns to them with a last smile, eyes sharp. “See you around, I suppose. And safe travels to us all.”

Somehow, it sounds ominous. The carriage door he’d come through earlier slides shut as Donghyuck disappears behind it, leaving an unsettling silence in his wake.

Donghyuck had been right about the bar, if the crowd in the lounge is anything to go by. Once the train has departed, Renjun ventures out to the shared carriages to explore, Jaemin following suit and making sure to hold open every door for him along the way.

“What are you doing?” Renjun hisses as they step into the lounge, where more than half the occupants of the train appear to be gathered with drinks in their hands.

“Being a good boy,” Jaemin answers, the perfect picture of faux innocence. “Can’t let my guard down when I have competition.”

Renjun shakes his head, exasperated. “I’m not having drinks. Not with Mark Lee.”

Jaemin grins. “Why not? He might be able to protect you from the Haerang Rail killer.”

Renjun jabs an elbow in the direction of his ribs, scowling when Jaemin dodges with a laugh. Thankfully, there doesn’t seem to be anyone within listening range; Renjun surveys the carriage’s warmly-lit interior, elegant wood paneling in deep mahogany lending the room a degree of exquisiteness. Some of the passengers are mingling, while others have chosen to sit alone on the upholstered seats. Donghyuck is visible by the bar, still Mark-less, and a different figure standing by the window catches Renjun’s attention.

He’s tall, with handsome features and a sculpted jawline. Like Donghyuck, he’s well-dressed, but unlike Donghyuck, he gives off an air of uprightness. A three-piece suit in plain navy, classy and dependable. As if he can feel himself being watched, the man lowers the bourbon in his hand and turns to look at Renjun. Or rather, looks just past him.

“Jaemin?”

Renjun feels Jaemin stiffin beside him. It takes a second for the easy grin to find its way back onto Jaemin’s face. “Well, if it isn’t Lee Jeno.”

Jeno makes his way over to them, a noticeable limp in his step. His smile is bright as he claps Jaemin on the shoulder, offering a hand to Renjun. The grip of his handshake is perfectly firm.

“Nice to meet you. I’m Jeno. Jaemin and I were housemates for a few years back when we both used to work in Jeonju. Are you two…?”

“Traveling together,” Renjun says quickly, before Jaemin can say something worse. “I’m Renjun.” He ignores the look Jaemin sends him, taking a step back as Jeno starts asking Jaemin about what he’s been up to in the last few years. It’s unusual for Jaemin to be the one socializing—Renjun is used to doing most of the talking when they run into people. Seeing Jaemin exchange pleasantries with an old friend is somewhat of a new experience.

Renjun watches them for a while, searching for any indication that Jeno might not be as nice or honest a person as he appears, finding himself disappointed when no such evidence presents itself.

“It’s been so long,” Jeno’s smile is genuine as he claps Jaemin on the shoulder once more. “I’m glad to see you’re doing well. Truly.”

There’s a playfulness in Jaemin’s eye that Renjun doesn’t often see. “You say that like you expected me to be dead in a ditch. Or maybe locked up somewhere?”

Jeno laughs, startled. “No, of course not. Nothing like that. Few people know better than I what you’re capable of.”

Renjun tunes out the rest of their conversation about Jeonju and the medical conference Jeno is on his way to attend in Beijing. After a while, Renjun decides to leave Jaemin in the lounge and go elsewhere in search of a distraction.

The dining car is empty, but the faint sound of a commotion drifts over from the nearest sleeping car—just the kind of excitement Renjun is seeking. He peers into the carriage through the glass panel on the door, taking in the sight of a distinguished-looking passenger and a cowering porter in the corridor.

“Watch where you’re going! Look, you got wine on my suit.”

This time, Renjun’s memory doesn’t fail him. He immediately recognizes the distinguished-looking passenger with a wine glass in hand as Zhong Chenle, heir to the Zhong electronics empire, whose suit probably costs more than Renjun’s entire wardrobe. Renjun hadn’t expected to encounter someone of his status on the Haerang Rail—somehow, he’d imagined the likes of Chenle only traveling in and out of the country by private plane.

Renjun sees, rather than hears, Chenle heave a sigh. The fabric around Chenle’s shoulders crinkles with the movement, suit a tad too large for him, though the excess space is easily filled by the confidence with which he carries himself. “What’s your name?”

“Park Jisung,” the porter stammers. “I’m sorry, I didn’t—”

“Jisung,” Chenle says. “Perfect. I was just going back to my room for a drink, but I don’t have anyone to drink with. You’ll do.”

“I—what?” Jisung mouth falls open. “Me?”

“No, the guy eavesdropping at the door behind you,” Chenle rolls his eyes, reaching out to take Jisung by the wrist. “Yes, you. Come on.”

Renjun freezes, but Chenle doesn’t spare him a glance as he turns and strides down the corridor in the opposite direction, pulling Jisung along with him.

Renjun doesn’t encounter anyone else in the sleeping cars—certainly no one as interesting as Chenle. He spends a while exploring the carriages, even returning to his compartment to do some unpacking before growing restless at the eerie quiet of his room. The prospect of drinks sounds more and more appealing as the sky outside grows dark; eventually, Renjun finds himself emerging from his compartment to seek company elsewhere.

The lounge is even more packed than before when Renjun returns. No sooner has he located Jaemin on the other side of the room and taken a step in his direction than he knocks into someone, upsetting the glass of drink in their hand. Renjun jumps back just in time to avoid the splash of liquid, an apology on his tongue.

“Oh,” there’s a faint flush on Mark’s cheeks that Renjun isn’t entirely sure is the work of alcohol. “We really need to stop bumping into each other like this.”

Renjun isn’t sure what’s worse—being in close proximity to minor celebrity Mark Lee, the flutter in his chest at Mark’s shy smile, or the deep red patch spreading across the front of Mark’s expensive sweater vest. Making a snap decision, Renjun grabs Mark’s arm and drags him over to the bar.

“This will stain if you don’t get it out,” Renjun tells him, dabbing at the patch with a napkin, trying to soak up as much of the pigment as possible.

“It’s—it’s fine,” Mark stammers, even though it’s clearly not. “Don’t worry about it, Renjun, I can just send it to the dry cleaner—”

“Mark! There you are. I’ve been looking all over for you.”

A familiar voice rings out as Lee Donghyuck slides into the bar stool nearest them, eyes bright. Renjun is almost thankful for Donghyuck’s forwardness as he introduces himself to Mark while Renjun is standing right there—at least Mark’s attention is taken off Renjun for a while—but soon comes to regret everything when Donghyuck leads the conversation to the train murders with impressive efficiency.

“What thoughts does an experienced detective like yourself have on the case?”

For someone of his fame, Mark seems oddly flustered by the attention. “It’s—interesting, for sure,” he answers, casting an uncertain look at Renjun, who busies himself folding the stained napkin in his hand into the smallest square possible. “You probably already know everything there is to know. Based on the news reports, that is.”

“But what do you think about the murders?” Donghyuck presses.

Mark hesitates. “Everyone’s talking about how the murders haven’t stopped despite the arrests. But what’s stranger is that there seems to be no pattern to them.”

“Different methods and types of victims,” Donghyuck agrees with a nod. “Strangulation, bludgeoning, someone even vanished—probably pushed off board. The victims were all men, but had little else in common. A revered academic, a police officer, a crippled victim of a fire. It seems almost random, and they keep happening.”

Evidently, Donghyuck knows his stuff. Renjun has no interest in a casual conversation about murder with not one but two people. He looks around the room and manages, by some miracle, to lock eyes with Jaemin, standing alone at the far end of the carriage with an empty glass in his hand, Jeno nowhere in sight.

Renjun sends Jaemin a pleading look and receives nothing in return but an obnoxious wink.

“It’s hard to speculate with so little information,” Mark says carefully. Judging by the way Donghyuck appears to be hanging onto his every word, Renjun isn’t surprised. “I guess the best we can do for now is to stay vigilant? Um. Renjun, what do you think?”

If it’s an attempt to include Renjun in the conversation, it’s sweet of him, though unnecessary. “I think I would like to avoid getting murdered on a train,” Renjun says, which Mark thankfully takes as his cue to change the subject.

The crowd in the lounge has thinned significantly by the time Renjun finally leaves, regrettably sober after only one drink and knowing far more than he had previously about the automobile trade of the nineteenth century. Mark offers to walk him back to his room, ever the gentleman, and Donghyuck bids them goodnight at the bar, opting to stay for a while longer. It’s just the two of them walking down the corridor when a crash resounds from the next carriage. Renjun exchanges an alarmed look with Mark before Mark pushes open the conjoining door to investigate.

The porter from earlier, Jisung, is muttering to himself as he kneels on the ground, gathering onto a tray several scattered items that it appears he’d dropped—a plate, a glass, some cutlery. Once he’s done he gets to his feet and turns around, startling when he sees Renjun and Mark in the doorway and nearly dropping everything again.

“Jesus,” Mark reaches out a quick hand to steady the tray. “You okay?”

“Y-yes,” Jisung stutters, ducking his head. “Sorry. I—I’m just clumsy. Please ignore me. Have a pleasant evening.” And without another word, he turns and scurries past them and down the corridor, eyes never leaving the ground.

If there was any lingering awkwardness between them before, Jisung’s appearance seems to have dispelled it entirely. Mark gives Renjun a helpless shrug as they continue down the corridor to their carriage. When they arrive at the second compartment, Mark turns to Renjun, much like he had earlier in the day.

“Have a good rest,” he says, blinking those sincere eyes at him. He takes a half-step forward and Renjun thinks for a moment that Mark might reach forward and take his hand, but instead Mark hesitates and says, “I’ll see you tomorrow?”

His smile is so pretty that it makes Renjun’s chest ache a little. “Yeah,” Renjun agrees, not yet knowing precisely what the morning will bring. “See you tomorrow.”

“A passenger has been found dead in his room.”

Renjun swallows around the lump in his throat, breakfast sitting untouched on the table in front of him. Around them, passengers trade whispers and fearful glances. Without Mark, it goes unspoken that any chances of solving the mystery are slim.

“If this happened last night, then the killer is on board the train right now,” Jeno says. “There are still eight hours until we arrive at our destination. Who’s to say the killer won’t strike again?”

Jaemin’s palm is warm against Renjun’s. Donghyuck is next to speak up, voice clear as he frowns down at his plate. “Every murder on the Haerang Rail in the last two months took place on a different ride. There’s never been more than one passenger killed at a time.”

“Even if that’s true,” a passenger protests. “This time could be different—”

“The culprits of the previous murders were caught,” someone else pipes up. “How do we know this has anything to do with those incidents?”

“The killer could be anyone—”

“Actually,” Jisung stammers, still deathly pale. “The doors between carriages are locked at night. For safety reasons. Which means that whoever—” he pauses, gulping visibly before continuing. “Whoever did this has to have been from Mark’s carriage.”

Another murmur ripples through the crowd. Renjun exchanges a look with Jaemin. Jeno has the room next to them—in the compartment shared with Mark, in fact. Renjun is certain Donghyuck’s room is in their carriage as well. There are three compartments to a carriage, six rooms, which leaves just one occupant unaccounted for.

“Seeing as we’re ill-equipped to handle an investigation on our own,” the conductor says stiffly, voice raised to be heard above the noise. “We’ll hand things over to the police as soon as we arrive at our destination. Until then, all passengers are advised to remain in their rooms with their doors locked.”

Renjun doesn’t need to be told twice; he stands, appetite long gone. Jaemin follows him back to their compartment in silence, tension thick in the air as other passengers hurry around them through the corridors. No words are needed as Renjun holds open the door to his room and Jaemin slips past him, plopping himself down on the bed as if it’s his own. After locking the door Renjun joins him, collapsing against Jaemin’s side and burying his face in Jaemin’s shoulder.

“You okay?” Jaemin murmurs, hand coming up to stroke Renjun’s hair in an unusual display of gentleness.

“Yeah,” Renjun sighs. “It’s just—Mark was a nice guy. He didn’t deserve to die.” A familiar numbness is beginning to spread throughout his body like poison. Mark is dead, he thinks, and for the first time, the reality of it sinks in.

He knows Jaemin is being nice because Jaemin doesn’t mention the amount of time Renjun had spent with Mark yesterday. His fingers are soothing against Renjun’s scalp. Reluctantly, Renjun sits back upright. “Who’s in compartment three?”

“The car salesman,” Jaemin answers easily. “And the rich kid.”

“Chenle?” Renjun blinks, surprised.

Jaemin nods. “So,” he says. “What do you think?”

You only purchase a ticket for an overnight train ride with a train murderer on the loose if you’re prepared to take a risk, is what Renjun thinks. He considers the individuals in their carriage. “Well—there’s Jeno. Obviously not him. Chenle is hiding something, but I’m not sure what.” Renjun thinks back to the odd stitching he’d noticed on the hem of Chenle’s suit when they’d passed each other in the dining car this morning. “Donghyuck is way too invested in the murders. He was talking to me and Mark about them last night. Just by listening to him, you would never suspect anything. Most people wouldn’t.”

“Most people,” Jaemin says softly, with a tilt of his head. “So, Donghyuck?”

Renjun closes his eyes, ignoring the uncertainty swirling in his gut. “Maybe. Yeah.”

Jaemin nods. “I think so too.”

Their conversation is cut short by a knock at the door. Renjun shares a look with Jaemin before Jaemin goes over to answer it, Renjun catching a glimpse of familiar brown hair in the doorway.

“You’re not Renjun,” Donghyuck says flatly.

Renjun doesn’t need to be able to see Jaemin to picture the leer on his face, pointed canines on full display. “Disappointed?”

“Do you need something?” Renjun calls, because the last thing he wants is to have to listen to Jaemin provoke-slash-flirt-with Donghyuck while blocking his only means of escape.

Donghyuck cuts to the chase. “Come to the dining car in ten minutes,” he says. “I’m gathering everyone in our carriage.”

Jaemin doesn’t move. “Including the killer?”

“It’ll be better if we’re all in one place. Power in numbers, and all that. Mark’s room has been locked—I checked—which means no one can go in there to investigate. But maybe we’ll be able to pool our knowledge and figure some things out.”

It sounds like a reasonable proposal. The conviction bleeds through in Donghyuck’s voice, set of his eyes determined ever since the announcement had been made over breakfast. But Donghyuck has also demonstrated that he’s incredibly smart. Renjun wonders how conceivable it might be that he’s guilty—it might depend on what information surfaces in the gathering he’s proposing.

“Okay,” Renjun says, before Jaemin has the chance to open his mouth and make things more difficult than they already are. “We’ll be there.”

Jeno is already seated at a table in the dining car when Renjun and Jaemin enter, expression troubled as he raises his hand to beckon them over. Jaemin takes the seat next to him, Renjun the seat on Jaemin’s other side. After several minutes Chenle joins them in the carriage, mouth set in a frown as he pulls out a chair at the adjacent table.

Donghyuck is the last to arrive. “Now that we’re all here,” he says, with the air of someone facilitating an important business meeting. “Let’s begin. In light of recent events, I thought it would be helpful for us to gather and discuss what we know about Mark’s death.”

Considering Mark is someone he’d had drinks with just last night, Donghyuck is remarkably casual about the whole thing. Nonetheless, his reasoning is sound. Renjun shifts uneasily in his seat, gazing around at the four other occupants of the room.

Chenle’s arms are crossed over his chest. “I don’t understand why I’m here. It’s not like I did anything wrong. It’s not like I killed Mark.”

“We’re all suspects,” Donghyuck emphasizes, eyes hard. “None of us have alibis. We’re here because we could wait eight hours until we arrive in Beijing and hope the police can uncover the truth, or we could do something about it.”

Chenle slumps in his seat but doesn’t protest. “I’ll go first,” Donghyuck offers. “I was awoken by a loud banging at three in the morning. It sounded like someone was trying to force their way into another room. Did anyone else see or hear anything out of the ordinary last night?”

Renjun glances over at Jaemin, who shakes his head.

“Not me,” Jeno says.

“Actually,” Chenle says slowly. “Now that you mention it, I heard something last night too. I wouldn’t call it loud, though? More like a faint sort of rattling.”

Donghyuck nods. “Now we’re getting somewhere. We might not have many leads, but—”

“Um,” interrupts a meek voice from the door. Five pairs of eyes turn towards Jisung, hovering uncertainly by the entrance. He seems to shrink under the combined weight of their gazes, words spilling from his mouth in a rush. “You shouldn’t be here. Passengers have been advised to stay in their rooms, so…”

Donghyuck claps his hands together loudly, making Jisung jump. “Perfect timing. You’re just the man I wanted to see, uh…”

“Jisung,” Chenle supplies.

“Jisung,” Donghyuck says. “Correct me if I’m mistaken. You’re the one who locks the doors between the carriages at night. And apart from the six deluxe rooms, the porter’s room is in the first carriage?”

“Yes,” Jisung stammers, face pale.

“That means apart from the five of us, you were in the carriage when Mark was murdered. In fact, you know the layout of the train better than any of us, and you had the perfect excuse to be wandering around in the middle of the night.”

“No!” Jisung’s eyes are huge, horror written all over his face at Donghyuck’s insinuation. “I would never—I didn’t kill him. It wasn’t me!”

Donghyuck’s smile is all business. “Then you’ll have no reason not to cooperate with us.” He gestures to the empty seat next to Chenle’s. “Have a seat, Jisung.”

Donghyuck is inordinately good at getting his way, Renjun realizes. He watches as Jisung shuffles over to the seat, nearly knocking a vase off a table and tripping over his own feet along the way, and Renjun isn’t sure who he’s more impressed by.

The unwelcome tension has found its way back into the air as Donghyuck looks slowly around at each one of them. “Now that we know for sure the killer is in this room,” he says. “Let the real investigation begin.”

Renjun never tells anyone the full story, but he first met Jaemin on a train.

It’s a several hours’ ride from Seoul to Gwangju; Renjun is looking forward to a quiet time alone in his compartment, with only the novel he’d brought for company. Naturally, the peace is broken twenty minutes into the journey when the door to his compartment is thrown open and a stranger stumbles inside.

His slacks are made of corduroy—that’s the first thing Renjun notices. His black hair is styled like the rich kids at university, and his facial features are sharp. Even back then, Jaemin was painfully handsome. Renjun finds himself too stunned to speak as Jaemin pulls the door shut behind him and scans the compartment.

“Do me a favor,” he says. No greeting, no explanation, no nothing. His voice is deeper than Renjun expects and just as attractive as his face. “If anyone comes looking, tell them I’m not here.” And then, before Renjun has time to react, Jaemin leaps onto the empty seat next to Renjun and hoists himself up onto the luggage rack above the seats.

Renjun does as he’s instructed. Informs the two men who come knocking that he hasn’t seen anyone pass by—not a soul. The men thank him with friendly smiles, and in spite of how much they don’t seem like law enforcement officials Renjun wonders, as Jaemin climbs down once the coast is clear, if he’s unwittingly been an accomplice to some kind of criminal.

“Are you going to tell me what this is about?” Renjun asks as Jaemin takes the seat opposite him, sitting with his hands in his lap like Renjun hadn’t just watched him fold himself like a pretzel to fit onto the luggage rack minutes earlier.

“Those were my colleagues,” Jaemin explains with a shrug. “They’re incredibly boring. I wouldn’t have lasted another minute in their company.”

“So you decided to hide from them. On the luggage rack.”

Jaemin smiles, showing off straight white teeth. Back when Renjun first met him, Jaemin was always smiling. “Exactly.”

Against his better instincts, Renjun is intrigued. Jaemin appears respectable—at first glance. Maybe it’s his good looks that distract from the dirt smudged in odd places on his clothing, the way the cuff of his right sleeve is singed. And then there’s the whole climbing-onto-luggage-racks thing. Renjun still isn’t sure what to make of that.

As if he can tell exactly what Renjun is thinking, Jaemin offers him a hand. “Na Jaemin,” he introduces. “I’m an inventor. Engineering intern by day, but I work on semiconductors in my spare time. One day I’m going to harness the power of the sun and stars.”

His eyes sparkle as he says it. “I admire your dedication,” Renjun says, accepting Jaemin’s hand after a moment’s hesitation. “Huang Renjun. Junior stock broker.”

“Renjun,” the way Jaemin rolls the syllables around in his mouth makes Renjun blush. Jaemin leans forward in his seat, unblinking. “You’re cute.”

Renjun’s cheeks are warm. “I’m—that has nothing to do with anything.”

“You don’t look like a stock broker.”

Renjun frowns. “Excuse me?”

“What do you want to be?” When Renjun doesn’t respond, Jaemin changes the question, eyes searching. “Why brokerage?”

Because Renjun’s father had been a stock broker, and his father’s father before him, and Renjun had never imagined a different future for himself. He already knows the answer to Jaemin’s first question. Ever since he was a child Renjun would find his way into his parents’ wardrobes, run his fingers over cotton and wool and the most expensive silks he could find. Brokerage is about flexibility and negotiation. But fabrics tell a story.

“I want to make clothes.” It’s probably the first time Renjun has admitted it out loud in his life. It’s strangely liberating. That’s the kind of feeling Jaemin inspires—an unwavering belief in your wildest dreams. The sort of confidence that leads you to get existential in a train carriage with a stranger you’d met ten minutes ago.

Jaemin’s eyes are bright. “When I’m famous,” he says. “I’m going to need a nice suit to wear to formal events. I might even need multiple of them.”

Renjun fishes his business card out of his bag, heart beating a little faster than usual. Junior stock broker, his title reads in black lettering, alongside the address of the company he works for in Gwangju. But maybe, one day, it will say something different.

Jaemin accepts the card. For the first time since the start of their conversation, Renjun smiles. “Then I suppose this won’t be the last we see of each other.”

“I saw him,” Jisung admits in a whimper. “I saw the killer last night.”

The room falls silent. “Explain,” Donghyuck demands.

Jisung keeps his eyes on the floor as he speaks. “You were right—it’s my job to lock the doors between sleeping cars. Usually around three in the morning. Last night, I was walking in the corridor after locking all the doors when—” He squeezes his eyes shut. “Someone ran past me, in the opposite direction of Mark’s room.”

Renjun tries to imagine being a porter on an overnight train, just doing your job, encountering strange figures in the middle of the night. And then, as if that weren’t bad enough, discovering a body the next morning. He shudders. Jisung isn’t doing too terrible a job of holding himself together, all things considered.

“Did you see his face at all?” Jeno asks.

Jisung shakes his head. “It was too dark. But he was tall.”

“He was tall,” Jaemin’s expression is neutral, but Renjun sees the corner of his mouth twitch. “That rules out literally no one except for Renjun.”

Renjun isn’t in the mood for violence—he shoots Jaemin a glare. Chenle hasn’t moved from his position. “What did you do then?” Donghyuck asks.

“I followed him,” Jisung answers. “I thought—I thought something might’ve happened, but he turned the corner to the water closet. I waited outside for a while and banged on the door to ask if he needed help, but there was never any answer and the door was locked.”

“Chenle and I heard that,” Donghyuck confirms. “That’s what the noises in the middle of the night must have been. My room is the last in the carriage, nearest the water closet, so they were loudest. Chenle’s is further, so it was faint. So far, everything adds up.”

Jisung looks miserable. “Why would I lie?”

“Is there anything else you can tell us about the figure?”

Jisung shakes his head after some thought. “Okay,” Donghyuck continues. “Let’s think about the murder weapon. A knife. Do we have anything to work with?”

“A knife from the kitchen,” Jisung says. “You’d have to steal one, but anyone could have done it, so that doesn’t really rule out—” He stops talking, eyes growing wide.

“Yes?” Donghyuck presses.

Slowly, Jisung turns to look at Chenle. “You ordered room service last night,” he says, voice hushed. “You ordered steak. I gave you a steak knife.”

Renjun exchanges another look with Jaemin as Chenle straightens in his seat. “You brought me a steak knife, which I returned once I was done eating,” Chenle says, incredulous. “You cleared my tray, so shouldn’t you know? I didn’t take the knife. You could’ve taken it and used it to kill Mark.”

Jisung pales. “I wouldn’t—”

“Do you remember seeing the knife when you cleared Chenle’s tray?” Donghyuck cuts in swiftly.

“I don’t know. I don’t remember. I—” Jisung hangs his head. “I dropped the tray in the corridor and everything went everywhere. What if I left the knife there on the floor? What if the killer—” he stops again, eyes going wide. “Was it my fault?” he whispers.

“Yes,” Chenle says, evidently still bitter over Jisung’s earlier accusation, at the same time Jeno says, “Of course not.” Renjun remembers running into Jisung in the corridor after drinks, when he and Mark were walking back to their rooms. That, at least, checks out.

“So we’ve learnt nothing,” Jaemin summarizes. “Nothing useful, anyway. The figure could have been anyone. The knife could have come from anywhere.”

A moody silence fills the room. Renjun looks helplessly over at Jaemin again, wonders how much more of this they’ll have to endure. It’s a lot to be forced to think constantly about Mark. Renjun doesn’t even want to think about how the rest of the journey is going to go. But more than that—

“I wish I could examine the body,” Jeno murmurs. “Just knowing that he died from a single stab wound isn’t a lot to go off.”

“Who said he died of a single stab wound?” Jaemin quips. “The conductor said he was stabbed fatally in the stomach. He didn’t say how many times he was stabbed.” Jaemin turns to look at Jeno, a dangerous glint in his eye. “Do you know something we don’t?”

And this is what Renjun had been worried about. A restless Jaemin is unpredictable at best—and a downright menace at worst. Harmless, for the most part, but likely to end up throwing unnecessary suspicion on himself. Jeno is meant to be his friend; it’s far too early for them to start turning on one another. Renjun shoots Jaemin a pleading look. Predictably, he’s ignored.

Donghyuck’s expression is stony. “Jisung?”

“I don’t know,” Jisung whimpers. “I’m sorry. I didn’t get a good look, I don’t know how many times he was stabbed. I just know there was a lot of blood.”

“It’s just a technicality,” Jeno says, betrayal mixed with confusion on his face as he looks back at Jaemin. “Stabbing someone in the stomach would be fatal, so I assumed that was the case. You can’t think I was the one who did it. I’m a doctor—it’s my job to save people’s lives.”

“Of course,” Jaemin says, though the glint doesn’t fade from his eyes.

A strained silence follows. Chenle is the one to break it. “I just thought of something,” he says, turning to look at Jisung. “You said it was too dark to see the killer’s face. But the lights were still on after midnight. What time do they go off?”

“They don’t go off,” Jisung answers, astonished. “The lights are always on.” He’s quiet for several seconds before the implication of his statement seems to hit him, draining the color from his face. “Wait—I can explain! Last night, just before I saw the killer, all the lights in the corridor went out. For a short while, like there was a power trip.” He looks nervously around, nibbling at his lower lip. “That’s the truth. I swear.”

“You’re the worst storyteller,” Chenle accuses. “How did you forget to mention any of this the first time?”

“The lights went out just in time for you not to be able to identify the figure?” Renjun asks, feeling a little bad when Jisung turns large, anxious eyes on him.

“It’s convenient,” Donghyuck agrees. “Maybe too convenient. What if we were to take Jisung’s word as truth—” Here, Jisung’s shoulders sag in visible relief. “And assume that the power outage was somehow orchestrated to hide the identity of the killer? If that were the case, there are two people who come to mind who have the skills to make it happen.” He counts off his fingers methodologically. “Firstly, Chenle, heir to an electronics conglomerate. Secondly, Jaemin, an engineer.”

Chenle knocks back his chair as he stands. “That’s ridiculous,” he says angrily. “Just because my family business has to do with electronics doesn’t make me some kind of expert. I majored in music.” He glares around at everyone. “Besides, why would I have brought up the lights in the first place if I caused the blackout?”

“I assure you,” Jaemin says. “I didn’t kill Mark.” He tilts his head, thoughtful. “Renjun can vouch for my character.”

If Renjun weren’t so stressed, he’d be biting back a sigh at Jaemin’s defense. And just when he thinks things can’t possibly get any worse, Jaemin turns to Chenle with a taunting smile.

“Can’t buy your way out of this one?”

“I could buy you,” Chenle snaps.

“Could you, though?” Jisung whispers, flinching as several pairs of eyes turn to look at him.

Donghyuck clicks his tongue. “Do you have something to share, Jisung?”

“It’s just—” Jisung looks once again like he regrets opening his mouth, possibly regrets being born. He points at Chenle without looking at him. “He’s not as rich as he pretends to be. His family’s company was sued because of money laundering and went bankrupt months ago, even though the public doesn’t know—he told me all this when he was drunk.”

A long silence follows his words. “Hey,” Chenle starts. “Don’t make things up—”

“It’s true,” Renjun finds himself saying. He’d suspected Chenle had been hiding something, and the evidence speaks for itself. “I noticed it when I first saw you. Your suits don’t quite fit, and the stitching suggests alteration or repair. It’s strange for the heir to a well-known electronics empire not to have an expensive tailored suit, isn’t it?”

Chenle shuts his mouth. “What does this mean?” Jeno asks uneasily.

“Picture this,” Donghyuck says. “You’re among the wealthiest families in the country, and your empire falls after you get exposed for money laundering. That stuff doesn’t happen on its own, of course. Maybe with the help of a famous detective? Mark unearths the scandal, and so it’s Mark who pays the price. It’s the perfect motive.” He glances over at Chenle, calculating. “All hypothetical, of course.”

“You think I’d murder someone because of my—situation?” Chenle demands, the embarrassment plain on his cheeks. “This is stupid. I didn’t kill Mark and I don’t know why we’re sitting here debating things like it will make a difference. I couldn’t have killed him anyway. I faint at the sight of blood.” And then, without another word, Chenle turns and storms from the room, slamming the carriage door shut behind him.

“That’s—an interesting defense,” Donghyuck comments, once the room has settled back into relative quiet. “I wasn’t expecting that.”

“It could be true,” Jisung mumbles, looking guilty at having lent a hand in the accusations. “He ordered his steak well-done.”

Jeno pushes back his chair and rises as well. “I appreciate the effort here,” he says politely. “But I think such matters would be best left to the authorities.” There’s a clear limp in his step as he crosses the room, disappearing behind the door seconds later.

“I have a headache,” Jaemin mutters, just loud enough for Renjun to hear. And then, to the rest of the room: “Is this it? Are we done playing detective?”

Donghyuck’s attempt to identify the killer may not have proven immediately successful, but it’s certainly given Renjun a lot to think about. He tries to shake the dread low in his abdomen as Jaemin takes him by the hand, and pretends not to notice the disappointment on Donghyuck’s face as they leave the room.

Weekday closing shifts at the tailor shop are quiet, as a general rule. Renjun is taking stock for the evening, adjusting the cotton suits in the display case at the store’s rear when the bell above the door tinkles, signaling the entrance of a customer.

“We’re closed for the day,” Renjun calls, without looking up. “Please come back tomorrow.”

“Oh,” says a startlingly familiar voice. “My bad. I didn’t realize.”

Renjun whips around, smooth fabric crumpling under his fingers. “Jaemin?” It’s been almost a year since their encounter on a train last summer. Renjun still thinks about Jaemin when he looks up at the stars in the night sky, wonders whether Jaemin has found a way to bottle their shine yet. And here he is now, in the flesh. “How did you find this place?”

Jaemin’s smile is cryptic. “I have my ways.” At Renjun’s hesitation, he changes his course. “Relax, I just visited the address on your old business card and begged until someone told me where you went.”

Jaemin looks every bit as stunning as the first time Renjun had met him. It’s actually unfair how good he looks in just a plain shirt and slacks—most men have to be wearing a blazer, at the minimum, before Renjun finds himself staring. “It’s good to see you,” Renjun manages. “If you want a suit made, you really should come back tomorrow. My boss is usually only here in the mornings and afternoons—”

“I didn’t come here to see your boss,” Jaemin frowns. “I came here to see you.”

Renjun wills himself not to blush. It’s a difficult task, especially when Jaemin makes his way over in several strides, gets all up in Renjun’s personal space just to ask: “But can you make me a suit? I can come back tomorrow, if you’re closed.”

Jaemin’s smile is perfect—perfectly sincere, that is. Renjun feels something deep inside of him quiver.

“Follow me,” Renjun murmurs. All in the name of good customer service, of course.

He leads Jaemin to the room in the back, gathers everything he needs as Jaemin stands in wait. Arms himself with measuring tape just as he’s seen his boss do. Renjun may lack hands-on experience—no customer would choose to have their suit customized by a mere apprentice tailor, after all—but he’s fairly confident he can do a good job. And Jaemin has a great body for tailoring, which shouldn’t come as a surprise. He’s tall, nicely proportioned. Renjun hopes Jaemin doesn’t notice the way his fingers tremble as he takes his measurements, from his chest circumference all the way down to his thighs.

“How have you been?” Renjun asks, because heart failure might be in his near-future if he continues to work in silence with Jaemin staring at him like that. “Have you figured out how to harness the power of the sun and stars yet?”

Jaemin’s smile does nothing to help with the heart failure problem. “I’m getting there. There are ways to convert light to other forms of energy, but none that work well, you know? It has to do with the elements, and the efficiency.” He pauses between sentences, as if taking time to convert what he has to say into a language Renjun will understand. Renjun probably couldn’t tell one end of a battery from the other, but he’d gladly listen to Jaemin talk science for hours just to hear the excitement in his voice. “I’ve made a lot of progress lately. I think it will pay off soon.” Jaemin grins. “I just need a suit to complete the look.”

Renjun nods in agreement. After measurements comes fabric selection. “Anything you have in mind?” Renjun asks, showing Jaemin a selection of their most popular samples, from wool to velvet, in various dyes. “Any particular colors? Any particular occasions?”

Jaemin looks them over thoughtfully. “How about something heat-resistant?”

Not silk, then. Tweed would be a good contender, but—Renjun runs through a mental catalogue of all the fabrics they stock, from lightweight to breathable to soft, until something clicks. “This one,” he locates a fabric and holds it up. “It’s a wool-synthetic blend, so more affordable while retaining most of the quality and versatility of pure wool. It looks gray, almost black, but when it catches the light just like this—”

“It shines,” Jaemin hums approvingly. “I like it.”

The rest of their exchange goes quickly. Renjun’s mind is abuzz as Jaemin pays at the front, with the promise of returning to collect his suit in several weeks’ time. “Congratulations,” is the last thing Jaemin says before leaving. “I knew you would make a good tailor.” And then he turns, oblivious to the emotion welling up in Renjun’s chest as Renjun watches him step out into the night.

It’s the first of many visits Jaemin pays the shop. When Jaemin starts asking Renjun out for drinks at the bar nearby, they talk for hours—that’s when Renjun finds out Jaemin has been traveling all the way from Jeonju to see him. Renjun tells Jaemin about the shop’s most outrageous customers and Jaemin tells him about the new discoveries he’s made, and before Renjun realizes it, Jaemin has woven his way into his life.

Lunch on the train is nothing short of suffocating.

The dining car is only half-filled, hushed chatter in the air as people mostly keep to themselves. Jisung seems to be the one paying the price for passengers’ reluctance to leave their rooms; he looks close to tears as he darts in and out of the carriage for the entire duration Renjun and Jaemin are there, either leaving with a tray of food or returning with an empty one. Donghyuck, Jeno, and Chenle are nowhere to be seen.

“Why are you so jumpy?” Jaemin asks, watching Renjun push an egg roll around on his plate.

It would be a lie to say Renjun isn’t on edge. The only reason he agreed to come to lunch at all was because it was preferable to listening to Jaemin’s nagging. His one saving grace is that none of the other passengers on board seem to know who shared a carriage with Mark, so at least no one is giving them strange looks.

“You know why,” Renjun mumbles.

“Because of Mark?” Jaemin is doing that thing where he says whatever he wants while keeping his expression perfectly straight. “Did you like him? Like, a lot?”

Renjun shoots him a withering look. “Why are you so calm?” he tries instead, pointing an accusing spoon at Jaemin.

“Oh, you know,” Jaemin says, which is a perfectly Jaemin-like answer.

After lunch, they return to their rooms. With less than half a day until arrival, it’s finally beginning to feel like the end is in sight. Renjun is arranging the contents of his luggage to keep his mind off things, a familiar possession catching his eye just as there’s a knock at the door.

He expects to see one of two people when he answers it. The first is Jaemin, who spends half his time in Renjun’s room anyway. The second is Donghyuck, who likely hasn’t given up on finding the killer just yet. Renjun is surprised to instead find Jeno standing outside his room, expression apologetic.

“Sorry,” is the first word out of Jeno’s mouth. “I know, given the circumstances, it’s really not the best time to show up to someone’s room uninvited—”

“No, it’s okay,” Renjun steps aside. “Come in.”

Jeno, clearly, is no threat. The way he complies and hovers uncertainty in the middle of Renjun’s room, too polite to sit, only serves to reinforce this belief. Renjun offers him the chair in the corner and takes a seat on the edge of the bed. “Did you want to talk to me?” he asks, after a while of watching Jeno stare worriedly at the carpet.

Slowly, Jeno raises his head to meet Renjun’s eye. “How well do you know Jaemin?”

“How well do I know Jaemin?” Renjun frowns. “What do you mean?”

“You’re—acquainted with him, obviously. But how well do you know him?” Jeno hesitates. “Do you trust him?”

Ah, Renjun thinks. The low hum of the train’s engine is suddenly all he hears. He can’t say he’d expected the question—but he’d known there was a possibility of something like this happening.

“You mean,” Renjun says, voice coming out colder than he’d intended. “Do I trust that he’s not capable of murdering someone?”

Jeno lowers his gaze. The look on his face says that he, too, had known Renjun might react this way. “I’m not accusing Jaemin of anything,” he says calmly. “It’s just—back when we were housemates in Jeonju, there was an incident.”

Renjun freezes. “An incident?”

“There was a fire at his workplace—a big one that got someone badly injured. One of Jaemin’s experiments was the cause. At home, he was always tinkering with things in his room. He had stacks of blueprints, proofs, things like that. I was there when everything was seized. Apparently, all of it was dangerous.” Jeno bites his lip. “It wasn’t publicized because Jaemin didn’t get in trouble with the law, and he never talked about it. But I heard of it because I was his housemate at the time. I think I’m one of the few who knows.”

Renjun waits a few moments to let that all sink in. “What are you trying to say?”

“What Jisung said about the power trip reminded me of the things Jaemin used to do,” Jeno says. “Even back then, it would’ve been easy for him. He used to mess with the lights in our apartment all the time.” He runs a tired hand over his face. “It’s not that I think Jaemin is a killer, but… I don’t know. When I think about it, I really don’t know that much about Jaemin at all.”

But Renjun does. Renjun is confident he knows almost everything there is to know about Jaemin as a person. The anger that rises in Renjun at Jeno’s words is so sharp that it surprises even him. It takes a minute for Renjun to calm down, to convince himself not to get worked up over things he knows he can’t change.

“Thank you, Jeno,” Renjun eventually says, quiet. “But I believe people are allowed their secrets. Just like how Chenle hides his family debt, and Donghyuck is desperate to find the killer for some reason, and how you walk with a limp, but only sometimes.”

He takes a tiny bit of satisfaction in the way Jeno grows pale at his words. “I—”

“Like I said,” Renjun interrupts curtly. “Everyone has their secrets. We all knew about the train murders and yet here we are on this trip. I’d be surprised if anyone was being completely truthful about who they are.”

“And what about you?”

“Me?” Renjun turns towards the wall separating his room from the other in the compartment. “If I hadn’t met Jaemin, I’d be wasting my life away in a run-down office building in Gwangju, doing something I hate. I don’t base my beliefs on hearsay.”

Jeno is silent for a long time. “I need a tea,” he mumbles as he stands, sounding exhausted as he turns to Renjun one last time. “I understand—really I do. And I’m sorry if I was careless with my words. Just… be careful, okay?”

Jeno is a nice guy. He obviously means well. Renjun ignores the guilt as he listens to Jeno leave, the door closing behind him with a click so soft it’s as though Jeno was never in his room at all.

When the minute hand of his watch approaches the hour, Renjun decides it’s time to act.

As expected, Donghyuck answers his door almost immediately. He opens it just wide enough to stick his head out, like he doesn’t want anyone to see the state of his room. Renjun catches a glimpse of papers strewn haphazardly across the floor inside; they remind him of the notes Mark carried in his briefcase, which feels somehow appropriate. And if Renjun’s suspicions are right, Donghyuck will be more than willing to cooperate with him.

“I think we should convince Jisung to unlock Mark’s door for us,” Renjun says. “Jisung was in the dining car earlier. If we hurry, we can probably catch him while he’s still there.”

“Mark’s door?” Donghyuck frowns. Renjun can practically see the gears in his head turning. “What do you think we’ll find there?”

“Clues,” Renjun says impatiently. “Or something. Which is better than the nothing we’re working with right now. Or do you have a better idea?”

Donghyuck doesn’t look like he does. Still, he regards Renjun warily. “And why do you want me to go with you? Where’s Jaemin?”

If Renjun didn’t know any better, he’d think Donghyuck was being paranoid. “Jisung isn’t going to agree so easily,” Renjun says. “You’re persuasive. And obviously, if we want Jisung to trust us, Jaemin isn’t the right person for the job.”

Donghyuck appears to consider it. “Fine,” he says after several seconds. “Let’s go.”

It’s a testament to how desperate he must be that Donghyuck doesn’t even shut his door properly, a sliver of the mess in his room visible as he takes off towards the dining car. Renjun toes the door shut before following Donghyuck, as a courtesy.

Jisung does turn out to be in the dining car, which is empty apart from him. He’s taking a break at one of the tables, staring into a glass of water like it contains all the answers to the universe, and perhaps unsurprisingly, he doesn’t like the sound of Renjun’s plan one bit.

“No,” he says, horrified. “I’m not allowed to unlock any doors for you. Especially not that one.”

Renjun shoots Donghyuck a look. “What if something in there helps us find the killer?”

“What if it doesn’t?” Jisung retorts, in a rare display of defiance. “Then we still won’t have found the killer, and I’ll be in so much trouble.”

Donghyuck steps forward. “Jisung,” he says. “I don’t think you understand. Once we arrive at our destination, this case will be in the police’s hands. And if they can’t find the culprit—they’ll choose a culprit. Just think about every one of the previous murders.”

Renjun had been right—Donghyuck is persuasive. Jisung’s face falls as Renjun turns Donghyuck’s words over in his mind. The police won’t choose a passenger at random; it only makes sense to pick the most likely suspect. And most passengers don’t seem to have the same guilty conscience that Donghyuck does.

After what appears to be a lengthy internal struggle, Jisung’s shoulders slump. “Sorry,” he says miserably. “I can’t. I’ll be fired.” He jumps in his seat as Donghyuck slams his hand against the table in frustration, offering a hasty: “But I’ll help in any other way I can, I swear.”

Donghyuck closes his eyes. “Fine. If you can’t show us, then tell us. Describe everything you saw when you found Mark this morning.”

“Okay,” Jisung whispers. He takes a deep breath. “We’re supposed to knock on a passenger’s door if they don’t show up for breakfast by nine. Mark didn’t answer, and his door was unlocked, so I—” Jisung shudders, squeezing his eyes shut. “He was just kind of there, at the foot of the bed. There was a knife from the kitchen. Lots of blood. I don’t really—” His blinks as he seems to remember something. “It smelled like smoke in there. His room smelled like smoke.”

“A smoker,” Donghyuck turns to Renjun. “Have you seen anyone in our carriage smoke?”

Renjun shakes his head.

“The first carriage is a non-smoking carriage,” Jisung supplies tentatively. “No one’s supposed to be smoking in there. Unless you want to be fined.”

Donghyuck frowns. “Are you sure the culprit was from our carriage? Could someone from another carriage have snuck in before you locked the door?”

Jisung shakes his head slowly. “No,” he says. “That’s not possible, because—” He trails off, eyes going wide.

“What?” Donghyuck asks tersely.

Jisung turns to him, face ashen. “After the person in the corridor ran past me and into the water closet, I waited outside for a while, thinking they might come out. But then I thought I heard a door shut from the other end of the corridor. From Mark’s room. So I went over and knocked to make sure everything was alright.”

“And?” Donghyuck presses.

“And Mark answered the door,” Jisung whispers. “He told me that everything was fine. That was after I locked the carriage doors. He was still alive.”

Donghyuck’s expression is dark. Renjun finds himself nodding along. “So that means—”

“It means our assumption that the figure in the corridor fled the scene after killing Mark was wrong,” says Donghyuck. “Mark was still alive while the figure was in the water closet. The figure wasn’t the killer. We’ve been going about this all wrong.” Donghyuck fixes Jisung with an unimpressed look. “Chenle was right about your storytelling skills.”

The dread that’s been plaguing Renjun since breakfast rears up again, making it slightly difficult to breathe. It seems they’re closer to figuring out the identity of the killer—and yet, somehow, further than ever. There are only a few more hours until the train arrives in Beijing.

“What now?” Renjun asks. Donghyuck, at least, seems to know exactly what he needs to do.

“We still need Mark’s door open,” Donghyuck stands, gesturing for Renjun and Jisung to follow him. “And we need to talk to Jeno. If he examines the body, he might be able to give us an estimate of the time of death.”

“I can’t open Mark’s door for you,” Jisung mumbles from behind them as they make their way through the sleeping cars, Donghyuck leading the way.

Jeno doesn’t answer when Donghyuck knocks, even after several seconds of waiting around. When there’s no response after a second round of louder, more urgent knocks, Donghyuck tries the handle.

Renjun’s heart is in his throat before Donghyuck pushes open the door fully. At first glance it seems like nothing is out of place—the curtains are drawn and the bed is made. Jeno is nowhere in sight. And then Renjun shifts his gaze downward.

“No,” Jisung gasps. “No, not again—”

Numb. That’s how Renjun feels when he sees Jeno lying motionless on the ground, empty eyes staring upward, the thinnest trickle of blood running from the corner of his mouth. There’s no knife, no visible wound, and Renjun doesn’t take a proper look before he tears his eyes away, trying not to think about how he’d been having a conversation with Jeno in his room not more than an hour ago.

Next to him, Donghyuck seems to have been shocked into silence. It would take an exceptionally good actor to make the face Donghyuck is making now, Renjun thinks to himself as he watches Donghyuck kneel down next to Jeno’s body to feel for a pulse. Jisung is still standing behind them, trembling like a leaf as Donghyuck shakes his head.

“He’s dead.”

Jisung shakes his head, disbelieving. “How?” he whispers.

There are no signs of a struggle. Renjun takes a cursory look around the room, eyes coming to rest on the half-drunk cup of tea sitting on the bedside table.

“Poison,” he whispers.

Donghyuck’s eyes follow Renjun’s gaze. “Jisung,” he says. “What happens when someone orders tea on the train? Who, besides you, could poison it?”

Jisung looks panicked. “It wasn’t me,” he says. “It could’ve been anyone. The kitchen staff make it, then they put it out on the counter to be delivered, usually with a note telling me which room to take it to. Anyone could’ve gotten to it in the dining car and—”

“Hey, what’s going on?”

Jisung jumps as a familiar voice floats over, Chenle making an appearance at the door. “Why are you all here? Are you having a meeting without me?” Chenle sounds upset. “I told you, it wasn’t me who killed—” his eyes widen as he peers into the room. “Is that…” He takes half a step back, swaying on the spot.

“Chenle?”

Jisung makes a noise of surprise, diving to catch Chenle as he crumples, eyelashes fluttering. Renjun can barely process what’s going on before Donghyuck is on his feet, leaving Jeno’s side to join them in the doorway.

“He said he faints at the sight of blood,” Donghyuck says, astonished. “He wasn’t lying.”

Jisung looks stunned as he holds the unconscious Chenle in his arms. Donghyuck’s eyes dart between Chenle and Jeno; Renjun knows what he’s thinking—the chances of Chenle being the killer are now drastically reduced. With Jeno down, there really aren’t many people left who could be responsible.

“Why would anyone do this?” Jisung whispers. “I don’t understand.”

But Renjun does, and he knows what he has to do. Donghyuck calls out to him as Renjun turns to leave, but Renjun can barely hear him over the thrumming in his ears. Between a poisoned Jeno and collapsed Chenle and hyperventilating Jisung, Donghyuck is in no position to stop him. Renjun forces himself to walk down the corridor with calm steps, one foot in front of the other, until he comes to a stop outside a familiar door.

Just be careful, Jeno had said.

Jaemin’s room is located in the same compartment as his, in the middle of the carriage. Renjun raises his hand to the door and knocks.

Unpredictability is part of Jaemin’s charm. Renjun grows accustomed to this early on; some weeks Jaemin visits the tailor shop more than once, some weeks not at all—certainly not with any consistency that lets Renjun know when to expect him next. Often he brings Renjun little gifts, like an unusual pocket watch or pair of silver cufflinks to match his own. Renjun keeps every one of them in the drawer next to his bed.

Tonight, Jaemin shows up with what looks like a tiny wooden duck on wheels. There’s a rectangular black panel attached to its back, and Renjun watches in fascination as the duck rolls its way slowly across the surface of the front desk.

“It’s a prototype,” Jaemin explains. “It works better under direct light.” He frowns. “It probably won’t move in a few days once the cell degrades. But it’s the first one I’ve made that actually works. It’s for you.”

Renjun has never seen anything like it. “It moves on its own,” he says, no stranger to the sense of wonder that comes with spending time in Jaemin’s company. He picks the duck up before it can roll its way off the edge of the desk, places it back at the starting line. “Like magic.”

“And this is just the beginning,” Jaemin promises. There’s an eagerness in his voice that peeks through whenever he starts talking about new discoveries, a familiar hunger in his eyes. “Imagine what could be done if we could harness energy from light on a large scale. Imagine the possibilities.”

“Lots of ducks?” Renjun tries.

Jaemin grins. “That too. But first I’ll need to improve the cell design, make sure it actually works properly. If I can secure funding for next year, I can make it happen. I have a good feeling about this one. Believe me, it’s going to be great.”

For all of his unpredictability, Jaemin is very consistent when it comes to what he wants. At the end of the day, passion got him to where he is. Curiosity is what drives him. When he says he’s going to make something happen, he works tirelessly to make it happen.

And because Renjun doesn’t know any better, he believes him.

“Come in,” Jaemin calls, voice heavily muffled through the door. “It’s unlocked.”

Renjun pushes the door open.

He knows what to expect since most rooms on an overnight train look the same. Jaemin’s room is a mirror image of Renjun’s own, except with the bed against the right wall instead of the left. Jaemin himself is seated in a chair in the corner, arms folded like he’d been waiting. Renjun makes sure the door clicks shut behind him before he speaks.

“You’re very calm,” Renjun says. “For a killer.”

That gets an unexpected laugh from Jaemin. His eyes are bright, hint of teeth showing as he stands, drawing himself up to full height. “And what are you going to do about it?”

With Jaemin’s legs, it would probably take him only three steps to cross the room. It takes Renjun five. He walks up to Jaemin, grabs him by the tie, and pulls him in for a kiss.

Jaemin’s mouth is familiar against his. Comforting, even. Renjun yanks him in deeper, a full second to savor the control he has over the situation before Jaemin’s fingers encircles his wrist, maneuvering them so that Renjun is backed up against the nearest wall. It’s a good enough distraction from everything that’s happening—or would be, if Jaemin could stay quiet for long enough to kiss him properly.

“I knew you liked bad boys,” Jaemin whispers, breath hot against Renjun’s mouth. He draws back suddenly, arms still caging Renjun in on either side. “Unrelated, but—how’s Jeno?”

“Don’t talk about other people when you’re kissing me,” Renjun mumbles.

“You’re cute when you’re being a hypocrite,” Jaemin reaches forward to pinch Renjun’s cheek, Renjun’s glare only serving to make his grin widen. “I’m not the one who spent all of yesterday flirting with the detective.”

“I wasn’t flirting—”

“But I guess you have to do what you have to do,” Jaemin sighs dramatically. “Right?”

Jaemin is making fun of him. He’d been holding back for most of the trip because of what happened with Mark, Renjun knows. The teasing seems to be back now in full force.

“Jeno’s dead,” Renjun says. Partly to change the subject, though it’s not like this one is any better than the last. “Everyone is gathered in his room right now.”

Jaemin nods. “Mission accomplished, then.”

Renjun breathes out slowly. “Yeah.”

Neither of them move for a while. It never gets easier, but Renjun has grown more accustomed over time to the paralyzing fear that accompanies death—initially he’d slept fitfully, waking up in the middle of the night imagining blood on his hands, but now if he doesn’t think too hard about it he can almost convince himself it was all a dream.

“You’re very soft,” Jaemin says, leaning in for another kiss. “For a killer.”

Renjun closes his eyes, lets himself melt into it. Jaemin steals his breath easily, the best kind of distraction. It’s exactly what Renjun needs right now. He pulls Jaemin closer, Jaemin pliant under his touch, lapping up every noise that falls from Renjun’s lips. Enough to make Renjun forget himself for a while, chasing Jaemin’s mouth when he pulls back abruptly with an annoying laugh.

“Easy,” Jaemin says, looking unfairly unruffled, not a hair out of place. “Wouldn’t want anyone to wonder why you look so—” he gestures to Renjun’s entire person. “Debauched.”

Renjun glowers at him. Jaemin plants a kiss on his mouth before gracelessly changing the subject. “Do we need to worry about Donghyuck?”

“He won’t figure out the truth,” Renjun says. “There isn’t enough evidence. Not against us, or anyone, really. So there’s no need to worry. Not as long as you did your part.”

“I hid the poison in Donghyuck’s luggage,” Jaemin assures him. “How did you lure him out of his room, by the way?” A pause. “You didn’t seduce him too, did you?”

Renjun feels himself flush. “Shut up,” he mutters. “I asked him to help me convince Jisung to unlock Mark’s door so that we could investigate.”

“Oh,” Jaemin grins. “That’s clever.”

They lapse into silence again, Renjun’s thoughts drifting to the room down the corridor. “Donghyuck was a good choice,” he says quietly. “He’s definitely trying to avoid the authorities—tax evasion, probably. He thinks Mark’s death will be pinned on him.”

“And it will be,” Jaemin says. “Thanks to us.”

Jaemin is right; anyone less than an expert at dodging the law won’t be so lucky. It’s unfortunate, because under different circumstances, Renjun is sure he would have appreciated Donghyuck’s quick mind—but there’s no point in thinking about that now. He and Jaemin didn’t make it this far just to get caught.

“Yeah,” Renjun agrees. “Thanks to us.”

Jaemin once tried explaining the Second Law of Thermodynamics to Renjun. Back when Jaemin was still living in Jeonju, and the highlight of Renjun’s week was seeing him walk through the doors of the tailor shop. Renjun used to hate the fact that they were so far apart. In hindsight, being able to see Jaemin's carefree smile, no matter how infrequently, was preferable to what came after.

It goes like this: for any given physical process in an isolated system, the combined entropy of the system and the environment will always increase with time. Entropy, in simple terms, refers to the degree of disorder of a system. According to Jaemin, the law explains why heat always flows from a body of higher temperature to a body of lower temperature. A hot drink always cools. A scrambled egg can’t be unscrambled. When it comes to irreversible processes, the universe favors chaos.

Renjun’s understanding is this: some things can’t be undone. It takes immeasurable effort to create, and a split second to destroy. The dreams you build for yourself can all vanish in the blink of an eye. One snip of the seams, and everything falls apart.

It’s just past three in the morning when all the lights go out, plunging the carriage into darkness, which is Renjun’s cue to act.

He slips out of his room and into the corridor as quietly as possible. From his left comes an alarmed voice in the distance that probably belongs to Jisung—Renjun trusts Jaemin will take care of him. Renjun turns right, feels his way along the wall until he comes to the last room in the carriage.

Mark answers his door almost immediately. “Renjun?” he says, and Renjun can picture the adorably surprised look on his face even without any light. He’s thankful for Mark’s impeccable manners when he steps aside without question. “Um… come in.”

As soon as Renjun has entered Mark’s room the lights in the carriage flicker back on again. “Huh,” Mark squints up at the ceiling. “That was weird. Power trip?” He seems to notice Renjun staring at the now-visible papers scattered across his floor. “Ah, please ignore the mess! I was working on some, um—stuff—when you knocked.”

“No, it’s my fault,” Renjun says quickly, as Mark bends down and starts gathering the papers into a pile. “Sorry. It’s late to be disturbing you. I was—”

“Don’t worry about it,” Mark says just as quickly. “I couldn’t sleep either.”

A stilted silence settles between them as Mark straightens. Renjun’s eyes fall to the notes in Mark’s hands. There’s a frantic rhythm starting up in his chest, but Renjun does his best to ignore it. “You’re investigating the train murders,” he says.

Mark nods after a second. “Someone has to do it.”

Renjun had known it since he’d caught a glimpse of Mark’s notes in the entrance carriage, even if Mark hadn’t revealed anything over drinks. Right now, Mark looks slightly wary, but not on guard. “How lucky for everyone to have a detective such as yourself on the case,” Renjun says lightly. “To make sure justice is served.”

Something about his choice of words seems to make Mark hesitate. Renjun’s interest is piqued. “You don’t believe in justice?” he asks. “But you’re a detective.”

“It’s—more complicated than that,” Mark’s grip on the papers in his hands tightens. “It’s not that I don’t believe in justice—more that justice is rarely black and white, you know? I’ve worked a lot of cases, and sure, you get the occasional guy out there who’s just doing whatever. But most of the time there’s a reason, right? A man steals food because he has a family to feed. A woman kills because it’s the only way to protect her child. People do crazy things because they’re backed into a corner, or because of what they believe in. People do crazy things for love.”

Mark Lee is quite the poet. Renjun is treading in dangerous territory. “What—”

He’s interrupted by a knock on the door. Renjun only has one bewildered second to wonder who it could be before Mark gestures for him to stand behind the door, out of sight.

“Is, um, everything okay?” comes Jisung’s concerned voice when Mark opens the door. “I thought I heard voices…” He trails off as Renjun listens in, careful not to make a sound. It would be bad if Jisung were to see him—but if not, this might work in Renjun’s favour.

“Everything’s fine,” Mark assures him. “Totally fine. Perfect. Thanks for checking, though.”

Jisung seems to accept this, apologizing for the disturbance and bidding Mark goodnight. Renjun lets out the breath he didn’t realize he’d been holding when Mark shuts the door. “Sorry about that,” Mark says with a sheepish smile, after enough time has passed that Jisung won’t hear them. “That was awkward. I mean, it would’ve been, if he’d seen you.”

“Yeah,” Renjun swallows. Awkwardness is the least of his worries. Jisung’s appearance had reminded him of the real reason for his visit; he finds his gaze slipping once more to the papers in Mark’s hands as Mark avoids eye contact, seemingly flustered.

“What were we talking about?” Mark asks. “Oh, right—justice is a complicated thing. But I guess some cases are more straightforward than others. Like with the train killer.”

The pang in Renjun’s chest feels a bit like disappointment. “What if they have a reason for what they’re doing too?” Renjun asks. “Don’t they deserve justice?”

Mark looks surprised. “Everyone deserves justice,” he answers. “But that doesn’t mean they can go around killing people for it.”

Renjun had expected this, of course. Even so, he finds himself drawn to the perfect sincerity of Mark’s smile, his earnest eyes. Renjun is good at improvising, but Mark Lee’s very presence aboard this train is something he couldn’t have prepared himself for if he’d tried.

“Kind of, um, a heavy conversation for this late,” Mark says with an apologetic smile. “Sorry. I know you don’t like talking about the train murders.”

“You can make it up to me,” Renjun says.

Mark blinks at him, cheeks growing pink as Renjun takes a decisive step forward, right up into Mark’s personal space. “Renjun? What are you—” He stops talking, eyes round, when Renjun places a hand on his shoulder, close enough to hear the hitch in Mark’s breath as he leans in.

How easy it must be to speak of justice when you still have a dream. When you hadn’t been sabotaged by colleagues you trusted, had your reputation dragged through the mud, and been left with nothing. Jaemin was the last person who would think of creating anything that would harm anyone. Mark had nothing to do with the incident—he’s just collateral damage—but it doesn’t matter. Renjun remembers the look on Jaemin’s face when, a year after the incident, he’d found the paper boasting new innovations in solar energy based on his own research, published under someone else’s name. How they’d stolen Jaemin’s work and stolen the light from his smile. And Renjun, forced to watch helplessly from the sidelines, had vowed to do anything within his power to make sure he never had to see that look on Jaemin’s face again.

Renjun will have to burn every page of Mark’s notes before he leaves this room. At this point, he’s practically got Mark backed against the wall. “You were right,” Renjun whispers into his ear, reaching behind his own back for the knife he’d concealed there—the one he’d picked up from the floor of the corridor earlier. “People do such crazy things for love.”

Renjun doesn’t remember exactly what happened the first time. He remembers the anger as he stood facing one of the people who ruined Jaemin’s life, a slow burn spreading to every inch of his body. He remembers raised voices. Jaemin had said he just wanted to talk to him, but Renjun remembers seeing the unrepentant look in the man’s eye, the sneer on his face, and feeling the last threads of his self-restraint snap.

He remembers thinking, murderers get the death penalty.

It takes him a moment to realize Jaemin is saying his name. All Renjun sees is the blood. The lamp that had been on the desk a second ago is in his hands—how did that get there? Renjun drops it like a hot coal, stumbling back as it hits the ground with a heavy thud. “Jaemin?” he says in a small voice.

There’s no response. For a terrifying second Renjun thinks Jaemin has left, but then he’s being pulled in, Jaemin’s hand on his cheek—that comes away with blood on it, too. Jaemin’s eyes are wide as he looks from Renjun to the unmoving body on the ground several meters away.

“It was an accident,” Renjun whispers. “I didn’t mean to—”

Jaemin shushes him, gathering Renjun in his arms, wearing a strange expression that Renjun doesn’t recognize. It’s the first genuine emotion Renjun has seen on his face in months. “It’s okay,” Jaemin whispers in a soothing voice that doesn’t match the furrow of his brow. “No one has to find out.”

True to his word, Jaemin helps him wipe the blood from his hands and get rid of all traces of evidence. No one finds out. The memory haunts Renjun like a ghost, paranoia sitting just under his skin like an itch he can’t scratch. At every turn he expects the police to show up and take him away, declaring that they know exactly what he’d done. Life as he knows it would come to an end. But as Renjun lies awake at night he realizes something else—for the first time in as long as Renjun can remember, Jaemin sleeps peacefully.

Two weeks later, Renjun drops a pair of train tickets in front of Jaemin on the kitchen table. “The other colleague who stole your work—he’s making an overnight trip tomorrow. There won’t be a better time to get him alone.” He watches as Jaemin blinks down at the slips of paper, connecting the dots in his head.

Renjun continues, “You said not many people know what they did to you because they covered it up, and that they’re all in different places now. That works in our favor. We can get every one of them before anyone figures it out.”

Jaemin doesn’t move. Renjun swallows. “It won’t undo what they did, but once they’re all gone, it’ll be a fresh start. You’ll be free.”

Jaemin is silent for a long time before he speaks. “Are you sure?”

Renjun knows what he’s asking. Are you sure you want to start this? Are you sure you want to risk everything? To Renjun, the answer couldn’t be more certain. The truth is that life as he’d known it had already come to an end the day Jaemin was falsely implicated. The Jaemin in front of him now is a shadow of the person Renjun had fallen in love with, and if there’s even the slightest chance of fixing things, Renjun will take it.

Renjun nods.

Jaemin finally looks up at him then, a familiar spark reignited in his eyes. He looks like himself for the first time in years. For Renjun, that’s enough.

Less than an hour till arrival and the numbness has finally faded.

Renjun is about to shut his luggage when his eyes land on the tiny wooden duck packed away in the corner, nestled among his other belongings. He’s picked it up before he realizes what he’s doing, turning it over in his palm. It stopped working years ago, it’s nothing more than an ornament at this point, but Renjun carries it with him wherever he goes. Jaemin would call him sentimental.

There’s a knock at the door. Renjun hurriedly replaces the duck as Jaemin enters.

“This was one hell of a trip,” Jaemin says as he finds his way over to where Renjun is securing his luggage. Jaemin peers over his shoulder, apparently deciding that Renjun isn’t doing anything important enough to warrant not being disturbed before leaning on him, hooking his chin over Renjun’s shoulder. “Lots of interesting people. Lots of improvisation. Shame about Mark, though.”

“He was a good detective,” Renjun says. He thinks back to Mark’s hasty scribblings, pages of information connecting the victims that Renjun didn’t have enough time to read before disposing of. “He was close to putting everything together, you know. He was onto you.”

Jaemin shrugs. “Unfortunately for him, I have you.”

Renjun turns to him, tilting his head upward for a kiss. It’s slow and sweet this time, Jaemin cupping his cheek with a gentle hand, like they have all the time in the world. The warmth lingers on Renjun’s mouth as they break apart, and Renjun finds himself blushing at the intensity of Jaemin’s stare. He breathes in, hands coming up automatically to smoothen the already-smooth fabric at Jaemin’s shoulders.

“This suit looks good on you.”

“I know,” Jaemin says. “You can’t seem to resist me.” He grins at Renjun’s soft sigh. “Been thinking about getting a new one, though. Something bolder this time. What do you say?”

“Yeah?” Renjun asks. He’s tailored so many suits for Jaemin by this point that he could cut the cloth for a new one by heart. It’s easy to make a suit for someone, when you have an intimate understanding of their body. “What do you want this time?”

“Something in red?” Jaemin suggests. “To hide the blood stains.”

“That’s not funny,” Renjun tells him.

“But you smiled.”

Renjun shakes his head in exasperation, extricating himself from Jaemin’s hold to gather his belongings in the middle of the room. He hopes there isn’t anything he’s forgetting. The victim, the story, the scapegoat. It’s not the first time, but this never gets any less nerve-wracking. Still, Renjun knows that the authorities can’t possibly figure the truth out if the only available evidence points to someone else. A seamless crime.

“Relax,” Jaemin says, like he can read Renjun’s mind. “We’re almost there. It’s almost over.” He gestures to Renjun’s belongings. “I’ll help you carry your luggages,” he offers. “Since you seem to like that sort of thing.”

“I hate you,” Renjun mumbles.

“You love me,” Jaemin says. “You would die for me.” He pauses, reconsiders the statement. “You would kill for me.”

Renjun can’t deny that.

“Do you regret it?” Jaemin asks after a pause. “Getting your hands dirty for me.”

“Of course not,” Renjun says. There isn’t a single thing he wouldn’t do for Jaemin, after all. Lee Jeno marks the sixth—there are only a few more people until they’re done wiping Jaemin’s past clean. In less than an hour, the train will arrive at the station, and they’ll be one step closer to finishing what they’d started.

Until then, Renjun will have to wait out the rest of the ride.