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 Feej for having read this over for me.

Lestrade shifts in his sleep, worry lines deepening on his face as the sirens drift past his window. Already, they are fading, only the echoes borne back to him on the summer night air, and his brow is smoothing again as he rolls over to press closer against the warmth at his side.

They never used to wake him. A man who has spent more than half his life on the force grows accustomed to the sound of sirens. Back then, he knew that most of the time, they signalled traffic accidents, sometimes actual crimes, on rare occasions ones in which the Detective Inspector himself would be involved, come morning. And he knew that there was nothing he could do about it from his warm, comfortable bed, so he would bury his face in the pillow and go on sleeping, unconcerned.

All that changed the moment Sherlock Holmes showed up to his second case.

The first time, Lestrade wrote it off as happenstance, a freak (oh, how he regretted using that word now) coincidence that the young man with the messy curls and disdainful expression had hit upon the right thing to say to spark Lestrade's brain into action and, ultimately, close a seemingly impossible case. Lestrade had been quite proud of that one, at first. And when he'd looked around afterward for his anonymous benefactor, to find out just how he had known what he'd known, the man had been nowhere to be found.
Didn't want police attention, Lestrade had thought then. The young man had seemed the type to cause trouble for trouble's sake, and it was probably better all 'round if he were simply left out of official matters altogether.
Then he had shown up again, several weeks later and in a completely different part of town. Lestrade's coup with the previous case had only led to more duties, more responsibilities covering more of London and yielding more paperwork than Lestrade had even thought possible. This case alone was causing mountains of the stuff, a new folder for every murder and a dozen forms each day the killer remained on the streets. The worry lines had started then, his forehead becoming permanently furrowed in a matter of days.
He had been examining a new body, fairly fresh by the looks of it, when his gaze had shifted from mottled bruising and dark bloodstains to a pair of surprisingly elegant shoes, black trousers, long coat, and, finally, a face that took him a moment to place.
He'd been about to ask, "Why are you here?" but the young man had forestalled it.
"Because you're in over your head. Again."
"But I – "
"Have missed everything of any consequence, I know."
When Lestrade recovered, he realized that the man was crouched over the body, muttering rapidly under his breath as he poked and prodded at the – the evidence, Lestrade suddenly realized.
"Look here, you can't just walk in here and start tampering with things! Who d'you think you are?"
The young man straightened and smiled, and Lestrade felt an odd sensation. "Sherlock Holmes," the man said, the smile becoming a grin that spread across his face for an instant before dropping back into cold neutrality. "And I couldn't possibly destroy any more evidence than your people already have, bloody great oafs."
"I – "
"It's a good thing I got here when I did." Sherlock was holding something pinched between the thumb and index finger of his right hand, raising it skyward for a better look. "Your murderer drives a red car, probably commutes from out of the city for work – madness; who'd drive in London? – and buys a lottery scratch card every day. Gambling addiction. You'll find he owes a lot of money, but why kill…?"
Lestrade stared open-mouthed as Sherlock's voice trailed off into thoughtfulness.
"What are you talking about? How do you know?"
"Don't look so stunned, it doesn't become you. Really, you're the Detective Inspector here. How did you miss all this?"
"All what?"
"Stop talking – Oh." And Sherlock had the answer, though Lestrade didn't know him well enough yet to realize just how much of it he had. "Try Kensington. A bank. Someplace with business clients."

Lestrade was left standing over a corpse, watching the swirl of Sherlock Holmes' coat as he vanished rapidly down the street.

But after that, Lestrade knew it wasn't just coincidence, knew that Sherlock would be back. He didn't know when, because he never knew what cases might grab the younger man's fancy, but every time he was called to the scene of a new crime, he was watching out of the corner of his eye for the swirl of a long, dark coat.

Of course, that wasn't how it happened, the next time Lestrade saw Sherlock. There was no grand swoop of heavy fabric, no narrowed eyes and cryptic clues. There was shouting. Sally Donovan, newly promoted and standing, for the first time, on the inside of the crime tape with a coffee brought to her by a constable who still had to stand on the other side. She had all but forgotten it, though, in her fury at the tall, dark stranger who had completely ignored her authority and was now completely ignoring her right to exercise it at the top of her lungs.
He hurried over.
"It's all right, Donovan. He's with me." Lestrade hadn't had the faintest idea that Sherlock was coming, but the only way Donovan was going to calm down was if he played this all off as perfectly normal and fully anticipated.
Sherlock had looked at her from the most supercilious angle he could manage (not difficult, from his height) and raised an eyebrow.
"Behave," Lestrade hissed, on impulse.
The younger man huffed a sigh, but obediently proffered a hand for Donovan to shake. "Sherlock Holmes, consulting detective."
It was Donovan's turn to raise an eyebrow. "That's not a thing."
"Oh, really," was Sherlock's disinterested reply, and instead of continuing the conversation, he took back his unshaken hand and followed Lestrade to yet another body.

There had been more paperwork to file after the end of that one, and it was only after he had gotten out of his office to go home (late, oh, he was tired) that he had discovered Sherlock loitering near the doors to New Scotland Yard. Or rather, not loitering, but waiting. He'd jumped up when Lestrade exited.
"What are you doing out here?"
"Is that how you thank me for having solved that last case for you?"
"I don't mean it that way. What I mean is, haven't you got somewhere to be?"
Sherlock shot him a look. "No."
Lestrade let his gaze travel up and down the man from head to toe. Still the elegant shoes, tailored suit, expensive coat. Sherlock wasn't exactly hard up. "I mean, you've clearly got…"
"Nothing on," Sherlock finished his sentence for him, "and nowhere to go. What about cold case files?"
"Er, what?" slightly taken aback by the sudden change in topic.
"Cold case files. Ones that were never solved. Have you got any?"
"This is Scotland Yard. We've got rooms full."
"Give them to me."
This had gone quite far enough. "I can't just give you a confidential file. I don't even know who you are."
"I told you, Sherlock Holmes," the young man had said, a slight smile forming as he remembered saying the same words earlier that day. "Consulting detective. Or I will be if you give me your files."
Lestrade had never heard of a consulting detective; in fact, he was pretty sure that Donovan had been right and there was no such thing. Still, there was no denying that he had solved all three cases he'd attended (barged in on) so far, and perhaps he could do it from a folder full of papers as well as he could over a grimy corpse in a back alley.
"All right," he had suddenly decided. "Come with me."

That he kept cold case files in his flat probably said more about Lestrade's solitary life than he would have liked to think. He had handed one to Sherlock, then turned his back on the younger man.
"Right, I'm going to bed. Don't take that anywhere," gesturing to the file.
Sherlock had looked up in surprise. Lestrade faced him again. "What?"
"You're letting me stay the night."
"You said 'nowhere to go,'" Lestrade reminded him.

In the morning, when he got up and began to make his usual bachelor's breakfast of coffee and nothing at all, Sherlock was sitting bolt upright on the couch, fingers steepled underneath his chin. It didn't look as though he had slept on the couch. He hadn't slept at all, of course, but that was another of Sherlock's quirks that Lestrade would only discover with time.

Somewhere along the way, the couch developed an indentation where Sherlock sat every night, or at least, on the nights when he didn't pass the hours by pacing back and forth in front of the coffee table (the carpet there, too, bore evidence of his constant presence). Somewhere along the way, Lestrade got used to preparing two cups of coffee – black, two sugars – in the morning, instead of just the one. And somewhere along the way, the gruff inspector stopped wondering where this anomaly in the dark coat and dark scarf had come from, and instead, began to wonder where he and the anomaly were going.

The others didn't question it anymore when Sherlock came with him on cases. Donovan had taken to calling him "freak" after having watched him disassemble a crime scene, piece by piece, using nothing but his mind, and reassemble all the pieces into the answer that eluded them. Anderson… well, Anderson had developed a distressing tendency to engage Sherlock in battles of wits. Distressing only because Sherlock never lost, Anderson never gave up, and Lestrade was afraid they would one day come to blows in the middle of a busy London street, thus ending forever the façade of professionalism he tried to maintain against laughable odds.
Lestrade didn't know how Sherlock chose the cases he solved, or why he left the other ones for the Yard to deal with on their own. He didn't know that Sherlock only took the cases that furrowed Lestrade's brow with concern, keeping him up late as he spread his hands wearily over the damnable evidence in front of him, so close and yet so far. He didn't know that Sherlock had taken to watching him in the evenings, keen eyes observing over the edge of yet another cold case file. On most nights, Sherlock had the actual cold case solved in minutes, yet maintained the illusion of labouring over it until Lestrade went to bed, at which point he threw the folder down in front of him and flung himself across the couch in some as-yet-unidentified frustration. But of course, Lestrade hadn't known any of that. Not until he had started watching back.

It had been an evening punctuated by furtive glances, Sherlock checking repeatedly to see if Lestrade had stopped watching him yet and Lestrade blinking away each time Sherlock's grey eyes met his dark ones over the creased documents in his hands. The case Lestrade was working on was a difficult one, and Sherlock hadn't seemed interested in helping. Nor was Lestrade getting any work done on his own, because his mind was more than half on Sherlock, and increasingly so as the night wore on.
The midnight striking of the clock startled both of them.
"Dammit!" Lestrade cried in frustration, slamming his hands down onto the papers that had fluttered out of order around him when he'd jumped at the chimes.
Sherlock regarded him noncommittally. His own surprise had barely shown, a flinch, perhaps, and a twitch of his lips. He would not normally have been startled, but he, too, had been distracted that night.
"Sherlock, if you're not going to focus on that case, come and be useful on this one."
"What makes you think I'm not focusing on the case?"
"You've done nothing but watch me all night. It's unnerving."
"Forgive me. I didn't realize that quietly observing you would prove such a hindrance to your work." A pause. "Perhaps if you weren't spending so much of your time doing the same to me…"
"Sherlock, focus on your own case. Or give me a hand with this one. Or, so help me God, find something else to do or somewhere else to stay, because you're driving me mad."
Sherlock unfolded himself from his praying-mantis position, his long legs covering the distance between the couch and Lestrade's dining table in just four strides.
"The librarian, obviously."
"How is that obvious?"
"Her hand."
Lestrade looked closely at the photograph, partly for appearance's sake (he couldn't see anything at all in the picture that he'd consider a clue), but mostly to cover the heat in his face as Sherlock bent over his shoulder to stab at the papers with one finger.
"There, it's solved. Happy now?"
"I have no idea what you're talking about, but okay. Now go and do your own."
"Solved."
"You can't have. You've barely glanced at it all night."
"Solved."
Lestrade pushed back his chair. "Fine, then. What do you want?"

The answer surprised Lestrade. Lestrade's response surprised Sherlock.

Two cups of coffee, black, two sugars. Lestrade carefully set his chair back upright; they hadn't even noticed that he'd stood up fast enough to knock it over the previous night. Nor had they noticed, shortly afterward, the papers fluttering to the carpet, papers that were now scattered and completely out of order, papers that would have to be sorted again – oh, it was going to take ages. Damn the paperwork.
He shuffled them together into a loose stack next to the leg of the chair. That would do for now. Anyway, the librarian was the murderer.

It was all he could do to keep from reacting when Sherlock made his entrance, though which reaction he would have chosen, Lestrade had no idea. At first, he almost burst out laughing. Sherlock had somehow managed to dig out from the back of the closet the worst gift Lestrade had ever received, a ridiculously garish paisley dressing gown, and drape it over his long form as if it were the close-fitting suits he wore each day and never seemed to remove.
Well. Until last night.
And that prompted the second reaction he didn't have, something deep down in the pit of his stomach, something that made him want to growl and leap the distance between him and Sherlock, touch, feel, own. And the dressing gown was the only thing Sherlock was wearing.

That was it, then. Sherlock had finally done it. He had driven Lestrade completely, totally mad.

He ran a hand through his hair and, instead of either reaction, turned his back and dithered with the coffee cups until long arms clasped loosely around him from behind and a low voice next to his ear said, "You've tidied. Pity. I liked the state we left it in last night."
Which very nearly caused him to spill both cups.

Sherlock enjoyed teasing him with it, the bloody great pillock. He showed up a lot more often at crime scenes now, even ones that he immediately dismissed under his breath as "boring" or "dull." He made sure Lestrade heard him when he said it, so that both of them knew what was coming. Then he'd make a game of it, brushing his hand over Lestrade's oh-so-subtly as they examined the body, muttering his deductions just a hair too quietly and too close to Lestrade's ear, standing over the inspector as they scoured the street for evidence so that the heat from their bodies mingled, Lestrade's breath came more quickly, and Sherlock stepped away again, smirking to himself at the effectiveness of his fun.

Those were never quiet nights. Not that Sherlock was ever quiet.

The couch slowly piled up with papers as Sherlock spent less time sitting on it and both of them spent less time working when they were at home. Home, yes, because although Lestrade continued to refer to it as his flat, it wasn't his collection of forensic monographs on the bookshelf that had once held classic novels, it wasn't his knife stabbed through the mail and into the wall at chest height, and it certainly wasn't his skull resting in silent repose on the mantelpiece. And although it was his awful dressing gown draped over the arm of the couch, it wasn't Lestrade who had put it there.

This, then, is the routine they have fallen into, warm nights spent on Lestrade's bed with the window open, midsummer sounds creeping in to surround them. Lestrade sleeps on the right; they did not arrange this, it just happened. Sherlock prefers the left anyway, because he rises often on sleepless nights to stand by the living room windows and look out at darkened London, and the left side of the bed is closer to the door.
Sometimes, Sherlock cannot be caged in so few rooms, and so he leaves, letting the door slip quietly closed behind him and listening for the catch of the lock. On those nights, he ranges through the streets, searching for stimulation, searching for something to work his mind. Two kinds of people move through the night, evading the yellow-orange streetlamps: Sherlock and the criminal underbelly of the city. Two kinds of people who were once not so very far separated, but Sherlock has chosen a side, and the other denizens of the dimly lit streets would do well to carry out their activities as far away from him as possible.
When Sherlock returns to bed, he slides silently between the sheets and never wakes the man on his right. But more than once, Lestrade has been roused from sleep by the harsh stutter of the telephone's ring, has answered, half-awake, and is dressed moments later as he dives for his front door to go and find Sherlock. His consulting detective is in trouble again; either he has run into the few members of the police force who do not yet know him and is being threatened with arrest, or he needs to use Lestrade's Scotland Yard resources, and it is always now that he needs to use them, never in the morning. Lestrade doesn't mind.
The sirens bother him, though, on nights when Sherlock is away. When they ghost past his window in the darkness, reflected red and blue against the bedroom wall opposite him, and he trembles with not-quite-irrational fear as he runs his fingers over and over the cool fabric next to him, wishing he knew that the sirens were not for Sherlock.

Sherlock gets injured far more often than is acceptable for Lestrade's peace of mind.

He never sleeps, once the sirens have woken him, until his consulting detective is back where he belongs. He knows he could text Sherlock, just to make sure he is all right, and Sherlock would respond. But that would be too much attention, and the last thing he wants to do is scare Sherlock away. This is not a permanent arrangement, he reminds himself every time Sherlock comes back to him, you cannot hold this man down forever. But that doesn't stop him from lying awake every time he leaves again, wondering if it will be this time.

Tonight, though, when he hears the sirens drift through his dreams and reaches out, he feels the warmth of another body beside him, and tonight, he does not need to worry. Sherlock is safe, and he can go on sleeping.