Chapter Text
PROLOGUE
*
The water is warm and insistent, pressing in on all sides. There is a moment of buoyancy, weightless and hovering, and then Sherlock sinks.
Sharks circle below; great grey shapes, distorted by the rippling water, deceptively placid. They pay him very little attention as he drifts downward.
He attempts to return the favour.
The wetsuit and mask have muted his senses. He is overly aware of his own heartbeat, the throb of blood in his veins, the pull in his chest that is an ever-deepening reminder of his last drawn breath. In contrast, the world around him is muddled, blurred and indistinct and very, very blue.
He does not have much time and so he refocuses, kicks, dives down towards the bottom, past artfully arranged stone carvings and gently waving plants.
There is a flurry of motion in his periphery and he turns, muscles tensed, ready to—well, he's not sure what, exactly, but he's not particularly keen on being eaten. However unlikely that may be.
It is not a shark that has caught his eye. It is, instead, a sea of eager faces pressed up against the glass. Children. His descent has drawn attention. This is inconvenient.
It is Saturday afternoon. Peak time for the London Aquarium. A crowd is unavoidable. Perhaps he could have timed this better. That's the sort of thing that John might have suggested.
He has, for obvious reasons, elected to exclude John from this particular jaunt.
His chest tightens. He is able to hold his breath for just over three minutes. He has practised, over the years. Sort of thing that comes in handy in his line of work. (Still, there is always room for improvement. Three minutes will tick by quickly, and he's likely to be intercepted when he returns to the surface for another breath. There will not be an opportunity for a second dive.)
It has been thirty-two seconds.
A shark glides past him, a bit too close for comfort, all flat black eyes and jagged teeth. His heart rate jumps, an involuntary but unnecessary response. He wastes time consulting his mind palace. Sand tiger shark. The jutting, razor-sharp teeth affect a ferocious appearance, but they are considered a docile species.
A larger crowd is gathering against the glass to his left. Topside, the attendant who fitted him with the suit and mask has almost certainly discovered his deception.
It had been easy enough to purchase tickets to the snorkeling experience, and even easier than that to distract the attendant and send him scuttling from the room in search of a better-fitting mask (and, perhaps, to have a bit of a cry—he'd been rather ruthless with his deductions). Sherlock had not wasted any time. He'd slipped into the water, bypassed the cage meant to allow tourists to experience a controlled adrenaline rush, and descended in search of his quarry.
Sixty-four seconds.
He gropes along the false seafloor, hands slipping through sand and silt, until he finds what he is looking for. He grins, and the mouthpiece of the useless snorkel drops from his lips.
There is a thrill of satisfaction, a familiar electric rush humming through his veins that comes with being right, and he lifts the severed human hand (male, sawed off at the wrist, skin showing signs of decomposition and only partially nibbled at by marine life) up over his head in triumph.
Only to remember the children at the glass.
He swivels, attempts to hide the hand behind his back. He is still grinning, he realises belatedly, and he clamps his mouth shut. His gaze slides past the crush of horrified faces—shocked and wide-eyed children, shouting parents, gleeful teens holding up their phones, at least three security guards (foolish, they'd never be able to get at him from down there), and—
Oh.
John. John, who is decidedly not supposed to be there, pressed flush against the glass, shouting something indistinct.
Sherlock breathes out, all in a rush. There is a painful twist behind his ribs, accompanied by the odd swoop of elation that only ever seems to happen when John does something unexpected. It makes him want to grin again, propriety be damned. He manages to control himself, but only just.
There is no room for smiling, here. Not here, in the building where Mary died. Which is why John should not be here at all.
John is still shouting, pounding on the glass, and now he's been tackled by a security guard, and Sherlock needs to breathe, he needs to be rising towards the surface, but he cannot pull his eyes away.
The tiger shark glides by again, close, very close, bumping his shoulder. Sherlock nearly drops the hand.
Ah. That must have been what John was shouting about.
His chest is very tight now. He turns away from the glass, kicks his fins. He keeps a firm grip on the hand. There is little point in trying to conceal it from view now.
The damage has been done.