I neither own nor profit from any of these characters; they are the property of Sir Arthur Conan Doyle, Steven Moffat, Mark Gatiss and the BBC.

If you see something that you think ought to be changed or improved, please feel free to let me know, if you'd like. Constructive criticism is always welcome.

Special thanks to ImpishTubist and LeDragonQuiMangeDuPoisson for having read this over for me.

De-anon from kinkmeme picture prompt for dark!Lestrade.

He can't sleep on nights like this. The electric fire of the half-dark, eerie thunderstorms reflecting on the fog, keeps him awake, sends tiny thrills of energy pulsing through his fingers until he has to grip the windowsill for support, nails digging long, shallow furrows in the wood, like every time.

Like every time he stays awake, remembering.

He keeps it hidden well most of the time; it's second nature now. He has to. It's not only the work – police force, well-respected, on his way up, Detective Inspector's just a quick stop on the way. There's that, of course, but then there are the eyes. The way Donovan looks at him sometimes, as if to peel the fine veneer of normal from his skin, lay bare and see what lies beneath… it makes him shudder, and he shouts at her, too loud, too hoarse, but it makes her look elsewhere and he breathes again. Anderson is even worse. His narrowed eyes, perpetually suspicious; he knows nothing, and there's no way he could, but even so…

The windowsill creaks in protest, and he releases it, tiny crescents of blood pooling beneath the fingernails, reminding him of what it looked like when it wasn't his. All blood is the same colour, cloying red, and he thinks that ought not to be true; he doesn't feel like his should be the same as all of theirs. It should run thick and tarry through his veins, some darker shade he's never seen or spilt, but that, he thinks, would give him away someday, so maybe it's better like this.

No use; there is no chance of sleep tonight.

Instead, he pulls away from the window and stands, illogically trapped between the window's greenish glow and the strange shadows of his bedroom, kamikaze bars across the floor so that he can't quite reach the door.

He never meant for it to be this way.

His mind is thrumming, useless, he can't push away the thoughts, and it's so crowded in his head, he wants them gone, he wants them gone, why will they not shut up, leave him alone, it's not time yet, too soon, too soon…

Only one way to stop them and he feels the shadows screaming for it, but he can't, he can't, it's far too soon, and if there's one thing he has learnt in all this time, it's that he has to be careful. One step too far, too fast, too reckless, and the pretence of a life he's built to cover up the real one will be gone. He can't afford that.

No, he will stay indoors tonight.

His hand creeps to the pocket of his jacket, hanging on the bedpost, carelessly abandoned earlier that night, when sleep seemed like a possibility. Fingers curl around the smooth, cold steel of – no, no, not that, not now, don't tempt yourself, you idiot, too close… his mobile, next to it, and with a forced twitch of his hand, he's pulling that out instead, dialling a number, the only one he knows is safe.

'Safe' is a funny word for 'mutually assured destruction,' but it's the best someone like him can hope for, and the closest he can come to being understood.

"Hello," comes the voice, chocolate-smooth, a show put on for anyone who might call in the night. Sherlock is good at this, second-best actor he knows, and they do pretty well together, falsifying barely-concealed contempt, exasperation.

Survival skills, but underneath, the dark, coiled things within them find mutual recognition.

"Sherlock."

His voice is low, hoarse with disuse and the tight, ice-cold feelings of the night, and Sherlock drops the façade between them instantly. He knows the meaning of the phone call, has made them himself, or used to, before John.

"Talk to me, tell me, give it to me," whispers Sherlock, thin, brittle words breathed on dry air, because they can fill a need in one another that goes far deeper than any crime scene in the daylight. Talking to Sherlock stills the murmurs in his head, sometimes, just for a little while. It doesn't last forever, but it closes up the dark, gibbering mouths that mutter to him, make him need things, wrong things, things that make his fingers twitch and tingle…

"It's a good night," he says, and knows that Sherlock, on the other end of the line, is nodding, seeing the same things he sees in twisting shadows and delirious light.

"You could," says Sherlock, "if you needed to."

"I can't, too soon, it's only been four days, it's never been like this before…"

"Let me get John."

John. John came as a surprise to both of them. If Sherlock is the second-best actor he knows, then John is so far and away the best that they both feel like amateurs beside him, bit-part players in a grade-school drama next to John's magnum opus, pizzicato fiddlers to John's philharmonic orchestra. It's never John whose chest tightens with need at the wrong time, whose fingers bear tiny scratch marks of silent witness to a crime that isn't mentioned. It's never John who makes these midnight phone calls, urgency too great for self-control.

John doesn't need them like they need each other. But he knows, he always knows, and that's something they should have noticed, if John weren't so goddamn good at what he does.

He remembers the night he met Sherlock, standing over a body in the street, minute shocks of recognition as he saw the telltale signs. Not just a murder, God, he knew it wasn't, he paced desperate circles on the tarmac, searching his mind for memories that weren't there, did I do this? It looked just like his work…

That's when his eyes met Sherlock's, standing on the far side of the yellow tape, flat grey gaze echoing his and they both knew.

Sherlock tossed off a few quick deductions, averting his eyes from all of theirs, and an arrest was somehow made. He's never asked who it is sitting in that cell; he trusts that Sherlock has chosen well. After all, both of them depend on it.

It's popular gossip around the Yard that he's the one who helped Sherlock get clean, that that's why Sherlock hangs around his crime scenes, solves his cases. And it's true, but not the way they think. He became a copper so that he could see and feel and live vicariously through the cases, fulfil the desires he didn't know how to dissuade. It wasn't enough, of course, could never be enough, but it helped a little on the harder days, when all the voices clawed at him at once. Safe, too, to be in law enforcement, just one step farther beyond reproach when something didn't seem quite right; the fact that he was on the murder squad – well, that was just the icing on the cake.

The drugs were Sherlock's answer to the need; when the clamour in his own head grew too great, he drowned it out with sweet chemical songs, destroying himself slow step by slow step. It was no more enough for him than other people's art written in blood on corpses at crime scenes, but by some loose definition of the word, it made him safe until they found each other.

Then, there were no drugs; the midnight phone calls kept them both hanging on by threads, by bloodied fingers gripping to the skin of the sane world they each pretended to inhabit, and when one of them came home, exhausted, covered in dark evidence of a night's urgent surrender, the other drew the lies of false conclusions, led the inquiries away until the clothes were burnt, the skin washed clean, and the wordless utterances silenced for a few weeks – more, if they were lucky.

They were not lucky often.

The telephone line hisses silently away; John must be busy, but he's coming – has to come, he needs help, stop me, stop me –

He was born this way, he didn't mean it, didn't know at first how wrong it was. He knows now, though, and yet, when he comes to his senses, finds himself over a struggling shape, soft, pale skin in the moonlight, so good against the blade

he doesn't stop, no, no, he savours every sound, every sensation

it's beautiful, the way the silver slips between the layers, bright blood spilling from the light into the shadows, and he drinks in every moment as the voices hush to silence, silence, and it's all he's ever wanted, just the silence

It lasts for a few moments and he cleans up, puts everything away, hides what needs to be hidden, takes care of it all, so neat and tidy, and by the time he's finished the voices are back, but at least, for now, they're quiet.

He can usually go a fortnight, maybe more, especially if the cases at the Yard are good. One-offs are boring (God, he sounds like Sherlock, they've agreed they have to be careful about that); it's the brilliantly twisted ones that please him most, only when he's himself he has to stand awkwardly about, frown, scrub the back of his neck with one hand. He's perfected uncomfortable; is an expert at businesslike. He's good at looking like it's just another job for a world-weary policeman who's got little else in life. Third-best actor, maybe, but even that has kept him safe so far.

Tonight, though, it's all going to go to hell if John doesn't answer. His hand is shaking – he's nearly dropped the mobile twice, and if he does, he won't be picking it back up; he's edging closer to his jacket, and he knows how comfortably his hand fits around –

"Hello."

And even as the darker part of him hisses and spits in anger, there is still a shade of rationality somewhere that thinks, oh, Jesus, oh, thank God…

"John."

"Tell me," says John, his voice crackling, greedy, down the line – it must have been a while for him as well, because he never sounds so eager. "Tell me about the blood."

John likes the blood. To him, it's proof of well-done work, a reward or better yet, a measure of success. He says it makes it real, and John would know; he joined the army for the blood, travelled a tour of duty as a medic so that he could feel his hands slicked with it, see the colour of it shine against his skin – and yes, eventually, staunch the flow and work his doctor's magic, closing wounds, applying bandages. He has a medal for it, Conspicuous Gallantry Cross, and the irony is flawless; the ribbon's stained with blood.

"I need it," he says, hearing the pressing heaviness of desperation in his voice, "the blood, it's – there's a storm…"

"I know, a storm, tell me," John's got control of himself again, sounds almost like the man who buys the milk, who cleans the flat, who wears old, ragged slippers when it's cold. He's got the most perfect disguise – all along, he and Sherlock thought that they were good, policeman and detective, but it's nothing next to doctor, wounded army veteran, the drab and quiet man who cannot possibly have hidden depths.

John's depths are wider, darker, than anyone would ever guess.

"I want to see it," he manages finally, "the lightning on the skin, rainwater mixing with the blood. My first night was like this…"

It's always been the same for him – the weather ramps up, ozone tightening the air, a buzz of nervous energy from static charges never quite released, and with it, his skin feels strained on his body, and the shouted discord in his head grows overwhelming.

But it's still too soon, he's only just… he wants to, God, he wants to…

That first time, when the voices stilled and he could hear the rain, that time, the blood was like a benediction on his hands, and he lay there beside his work and let it wash over him, adrenaline and blood and rain and marvellous relief, and then he laughed, because he'd never guessed the answer was so simple.

"Stay with me," comes John's voice, but they both know it's a lost cause by this point. "Come on. Tell me something, anything."

"Not going to be enough," he says, "I can't…"

"All right," says John, "all right. Stay there. I'm coming."

He isn't sure what John means by that I'm coming. Are they going to sit there, in the middle of his bedroom floor, and talk? Talking won't help. And yes, while John could stop him going out, and should, and should, oh, should, he's pretty sure that that is not what the ex-army doctor has in mind. That's something Sherlock might have tried to do, but John…

John likes to live vicariously, too, and sometimes, seeing one of them return bloodied up to the elbows (John always prefers it if there is blood – wide, toothy grin; high, thready giggle) is enough for him. John's work is beautiful, artistic; he can afford to be selective. When John works, it lasts for weeks.

So no, he doesn't think John wants to stop him, but he doesn't know what else he might have planned, and when John arrives at his flat (no key; Sherlock has long since taught them the science of the lock), he is sitting cross-legged in a shaft of watery green light, flicking the knife open, closed, open, closed, open…

John folds his hands around the knife – closed – and says, "Come on."

Come on.

Let's go. It's time.

No – no – too soon – four days –

"It doesn't matter," John tells him, and in the shifting moonlight through the thunderclouds, his grin is weirdly twisted, not quite right. "I'll take care of it."

He's going, now, the knife cool in his hands, with John.

Need bubbles up within him, filling his throat and cutting off his words – it's time, it's time – and John knows what he does, and how he does it –

"Don't worry," John says, grin almost halfway back to normal, "you aren't alone."

They slip down through dark alleys; he's hunting on the ragged edge, need for release so desperate he forgets to control his breathing, not that he can hear it anyway over the roaring in his head. John follows after, letting him lead, moving with economy of step that speaks to extensive practice. This is his night, his need, but it's all been so sudden, he's had no time to prepare, and his control is faltering. That, he knows somewhere in the deeply-buried rational part of his mind, is why John is with him now.

He sees movement, his hand sliding up underneath his untucked shirt to rest at the hilt of his pocketed knife. Not this one, no, not this time, not tonight, he wants to choose, the first one that comes along won't be enough to silence everything, and they brush past the lonely, hopeless figure of a homeless man, thinking, You have no idea how close you came to death tonight.

They move to brighter streets, amber glow of sodium streetlamps warring with the sickly glare of storm. John touches his arm carefully, this is dangerous, they're too exposed. He knows that, but it doesn't seem to matter – this needs to be what it is, it needs to be enough. He has to know the voices won't be back again tomorrow (it's only been four days, too soon).

Around a corner, hazy shapes of people, wrong ones, no, not good enough. They move along. It's cold. John has a coat, he doesn't, and the tingling on his skin tells him that if this were an ordinary night he'd be too chilled, they'd go inside. It isn't, and they don't, and then he turns another corner –

sees a dark uniform, high-visibility jacket, black and weirdly green against the light

looks at John

this one

now.

John's eyes widen and he pulls him back around the corner.

"Are you mad?" he hisses.

They just look at one another for a moment. Middle of the night, they're out hunting in the streets, one goal in mind, crystallized in the form of perfectly-balanced knife, perfectly-unbalanced mind. The question is rhetorical.

He isn't going to say a word. It's this, it's right, he knows it, feels the pull deep in his chest. Police officer, yes, it's good, it's big enough, the risk is palpable and beautiful . He senses the sting of wanting in his fingers, throbbing through his teeth, his whole body wants this, and his mind is helpless to disagree – not that it will, the fragment of reason it contained before his hand closed on the knife is long since gone.

Something moves behind John's eyes, dark and flickering, and he can see his victory reflected there. This is something even John has never done, and that's enough to send a needle up and down his spine, intensely painful thrill, no more waiting, no more.

They go.

This isn't how he normally does it, this frantic search through random streets for strangers who whisper to his subconscious compulsion. He normally has the time to be methodical. Man his age, single, walks the way he does, dresses with care… he normally finds himself out cruising Old Compton Street; it's never very difficult to find the ones who won't be missed.

He doesn't know how Sherlock and John do it (it's not something they talk about, except in desperate midnight confessions, and never the details), but he's seen Sherlock there too, vaguely, in the shadows, on some of the nights he's gone, and Sherlock wore revealing shirts, tight jeans, and is not gay, so maybe it's convergent evolution, easiest means of finding what they want.

His eyes meet John's over the head of their intended target, and they move, and then they've got him down, struggling, but John knows how to silence him with one hand, while the other rests on his companion's shoulder, grounding him, keeping control, not here, while they overpower and subdue.

Sherlock carries a needle – this he knows – but he has always preferred to work with his hands.

Sherlock also carries a set of instruments, and he glories in secrets half-guessed-at of what Sherlock might use each one for, but for himself, he keeps only the knife.

It's in his hand now, resting on the fragile surface of the man, ready to curve in when he lets it, wicked, permit the flesh to tear like fibreglass, to fall apart unresisting under his careful manipulation – he may work with his hands, but he's not brutal.

John pulls him away, drags them both down the alley, out of sight; they were too close before, but he is trembling with urgency, deafened by the rush of voices screaming for this, for blood, release

he presses down

strangled sound

quick twist of hand, then slow, deliberate pressure

John catches his arm, makes the knife jerk in his hand – no, wrong, more blood, too much – but John likes that

deeper

delicate lines etched out, the skin peels back, finely lined muscles, fibres separating, beautiful

he doesn't know how much time has passed before his work is done, artistry carved in skin and sinew, voices from screaming into whispers, into silence, he collapses on the rain-slick tarmac, shaking.

He can't breathe for a moment, can't do anything to destroy the stillness won at such inordinate cost, and there is nothing but the rain and his own tremors as he shudders against the cold, wet street.

Quiet scrape of sound behind him and he rolls, clothing soaked through with blood and water, to see that John is there. He's doing something, the police officer's gone –

oh, God, police officer

what did I do

what did John let me do

"It's all right," John says, and he's wiping off the knife against a strip of crisp, white cloth cut from a Metropolitan Police uniform shirt, rain darkening his hair and beading on his hands. He passes back the knife (reverent gesture, this is a tool of their shared trade and not John's to possess).

His voice is choked when he first manages to speak. "But – where – "

You should have stopped me.

"I took care of it."

Just as John promised, but now the terrible, tearing need is gone, and those words alone are not enough to reassure him, not when he's capable of enough impartiality to know that there is a boundary that was overstepped tonight (not just overstepped, but shattered) and the consequences could spell the end of everything.

"How?"

John smiles. If possible, it's even more unsettling than the last time, something in the angle of his jaw or in the way his lips curve when he doesn't show his teeth. "The way I always do."

They never talk about the details, but the Homicide and Serious Crime Command never find any of John's bodies, either.

He nods and pulls his jacket closed around him (bloodied, stained, but that's the reason why all of the suits he owns are black), ready to leave. John's coat, too, is black, but his shirt cuffs are darkly stained and he shoves his hands deep into his trouser pockets. They stand opposite each other, searching for signs of the night's activities and, finding none that will be easily noticed (only lost shirt button, torn collar, dishevelled hair), make their rapid way along the walls of old brick buildings, keeping to the corners that will take them home unseen.

John brings him to Baker Street, where Sherlock is pacing the length of the living room, mobile in one hand, the other gesturing pointlessly in the air. This is no game, the rules don't change at random, and yet John has done something tonight that isn't in the playbook.

If only he knew just how far from the line they've strayed this time.

John vanishes upstairs and comes back a few minutes later, hands scrubbed clean, fresh shirt and oatmeal jumper. He looks normal, harmless. He looks like a man who won't be caught.

The ruined suit jacket comes off as well – no point in hiding himself here, crimson-stained shirt front fading to rusty brown under the yellow lamplight. They sit across from one another, silent, in the dimly-lit flat, until John smacks the palms of both hands against the edge of the table and stands, hovering behind his chair.

"Tea?" he offers.

They duck their heads appreciatively, his "just milk in mine" and Sherlock's usual "three sugars, please." There's nothing at all unusual about it, except that it's half three in the morning and his shirt is sticking to his chest uncomfortably.

John carries in the cups, two at a time and then his own. "We're out of biscuits," he apologizes.

They raise their cups to one another, as close to normality as they will ever be, and drink.

He hears the faintest whisper of a voice, but it will wait.