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 MorganStuart for having put ideas into my head and then encouraged me to post them. I humbly suggest you all read everything those two have ever written.

Inspired by the prompt: "To help Sherlock get the information he needs to solve a case, John and Lestrade spend a long, cold, and unexpectedly dangerous weekend undercover on the streets posing as part of Sherlock's 'homeless network.'"

The first thing John noticed was that Lestrade wore his clothing to the point of disintegration.

It felt a little strange, being wrapped in the detective inspector's old, grey tracksuit bottoms and T-shirt. Stranger still were the gusts of wind he could feel through them, cold fingers of a London winter tickling his spine, raising the hairs on his arms and making him hunch up even smaller in the already-too-large clothes.

"Why the hell didn't you replace these months ago?" he asked, and thought he should probably have said 'years.'

"They're comfortable," argued the DI. "And at least you know where yours came from." Lestrade was dressed in grubby jeans and a stretched-out cotton polo neck of dubious provenance, both of which had been found for him in the bin of unclaimed personal property left behind by discharged prison inmates.

John shuddered. "Don't think about it too closely."

"I wasn't, until now."

Sherlock appeared around the corner. "Ready?"

"Yeah."

"Do you understand the system?"

"Yes, for God's sake, Sherlock, you've explained it to us three times already now."

Lestrade added, "If you were ever this forthcoming at crime scenes, you'd be a lot more popular with forensics."

"I think," Sherlock replied, "that Anderson's issues with me stem from my being rather… too forthcoming."

"And yet you don't stop."

"No."

Sherlock seemed to think that that stood for itself, so Lestrade shrugged and dropped the subject. John looked both of them up and down. "Do we get jackets?"

"One of you does."

"One of us?"

"There was only one." Sherlock held up a dull green windcheater with a fleece lining and questionable stains along one sleeve.

John and Lestrade looked at one another, neither one particularly eager to add it to his ensemble.

"You'd better take it," said Lestrade. "You've only got short sleeves."

"Right. Remind me, Sherlock, why we've got to do this?"

"John, we've been over this – the only way we're going to find anything out about those murders is to gain insider information. I need insiders."

"You have an entire homeless network. Why d'you need us to do this?"

"They won't talk. I can pay them for information I need, but this is different. The killer is quite clearly attacking the homeless and the poor, and I pay them in fifty-pound notes. The community protects its own; they won't let someone like me in on this."

"You'd think they'd want Sherlock Holmes on the case."

"I'm not Sherlock Holmes to them, John. I'm just a man who gives them handouts in exchange for other people's secrets. I'm the last person they would want… investigating."

Lestrade sighed. "Well, let's get on with it, then."

They huddled together near the side of the river, looking at the way the bridge lit up at night.

"Funny," said Lestrade. "I always reckoned if I ever had to sleep rough, it'd be under a bridge."

"Put much thought into it, then, have you?"

"Mmm." But the DI didn't seem to be interested in elaborating, so John said, "If it's a bridge you want we can go and have a look 'round."

"I'm not hung up on the bridge. When d'you suppose Sherlock will be around?"

"Dunno. Why?"

"Aren't you hungry?"

"Starving. I'd forgotten because I'm bloody freezing."

"Well, whenever Sherlock comes by with the… payoff, we can get something to eat and maybe get warm for a bit."

"You sure we can't just find a place to stay? No Second Night Out and all that?"

Lestrade shook his head and John thought he detected something in the set of the older man's jaw, the way his eyes slid over the black water of the Thames and came to rest again on the bright lights of the bridge and its surroundings.

"He targets rough sleepers. We won't find out anything if we go to a shelter."

"Trust Sherlock to make this as difficult as possible."

"Hey." Lestrade nudged John with his shoulder. "We're all right. Only been out here a few hours. People manage for weeks."

John moved closer, appreciating even the small amount of warmth the two of them could share. "I s'pose. Still, I wish – "

He was cut off by the appearance of Sherlock Holmes walking rapidly down the street, and stared mutely until Lestrade muttered to him, "Change."

"Change – any change, sir?" John managed, loudly enough to reach Sherlock despite the chattering of his teeth as the sentence trailed off. It would do, at any rate, and it brought Sherlock over to them with a folded bill between his fingers.

Lestrade stepped back, away from John, as the money changed hands. "Thank you," he said, softly, echoing John's much more audible gratitude. It didn't matter; Sherlock would hear both and know that while John's words were part of their established script, Lestrade's were meant sincerely.

Without watching the younger man leave (important; Sherlock had warned them that it would look very suspicious to focus on him instead of on their takings), Lestrade took and examined the note they had been handed, wrapped around a scrap of paper on which Sherlock had written,

Whitechapel, moving west

"How does he know?"

"More importantly, if he can do that, why are we out here?"

"'To observe,'" John quoted, an edge of bitterness creeping into his voice.

"Come on," said Lestrade. "Let's go and find someplace that's still open. What d'you want to eat?"

"Anything warm," John said. "Anything we can afford."

"We've got a tenner."

"A – I'm going to kill him!"

"Why?"

"His proper informants get fifties!"

Lestrade passed John the banknote and ran a hand through his already-tousled hair. "Well, add it to the list of things we're going to kill him for when this is over. In the meantime, I suppose it's the Saver Menu for us."

"Lovely," said John. "Perfect."

Later that night, the wind picked up and John caught Lestrade crouching down behind a wheelie bin, trying to avoid the worst of it.

"You can't spend all night like this," he said, hauling the DI to his feet. "We've got to find somewhere out of the weather."

"Can't. Have to stay outside." Lestrade's sentences were brief, the shivers running through him forcing him to bite off the ends of his words or risk his voice giving the lie to his curt statements.

"Fine, we'll stay outside. We don't have to do it here."

They walked along the embankment, past stragglers clearly wishing they had not stayed out so late, past dark-shadowed people in dark coats who avoided the sodium glow of the streetlamps, past shuttered buildings and boats closed up at their moorings, until they warmed a little from the constant movement and found themselves in a back alley in Blackfriars.

Lestrade frowned up at tall, imposing sides of grey buildings, mediaeval Gothic styles contrasting with cast ironwork and steel.

"Are you sure?"

It might just have been the Victorian air to the place, but he wasn't sure he wanted to let down his guard here at all, much less find it a viable place to sleep.

"It's sheltered – a bit, at least," said John, "and none of this has got much point if you're just going to die of exposure."

"Think it'd crack Sherlock's façade a little?"

John grinned at him. "You see through it too?"

"Don't tell him. God forbid he thinks we think he cares."

"You're right. I can picture it now. 'He was a witness, John. Now who will I get to sleep on the streets for me for no good reason?'"

"Keep your voice down," but Lestrade was chuckling nonetheless. "Every petty criminal and his brother'll know what we're up to if you're not careful."

"Considering we don't even really know…"

"Don't forget. 'Whitechapel, heading west.' We'd better stay in the more frequented areas – we're no good to Sherlock if we don't go where there are other people."

"Right, yeah, of course. We've got to be insiders."

A huff of breath from Lestrade, whispered answer to a laugh.

"I ever tell you about the last time Sherlock had me out here?" John said conversationally as they moved on in search of more populated alleyways.

"Last time?"

"We were looking for that assassin, you remember, from – " He cut himself off, remembering the weight of that night; following his friend thoughtlessly into danger, crazy patchwork of memories from the planetarium, the Golem standing silhouetted tall against the lights and Sherlock, both fists raised and yet useless against his adversary of the moment.

Basically, then, a metaphor for their entire lives.

"From… yeah, I remember." Lestrade wasn't going to say it either, and John felt a stab of gratitude for that.

"At least that time he let me have my…" and again, a topic that could not be discussed.

"Your own clothes and a proper jacket," Lestrade filled in smoothly, "yeah, well."

John nodded at him and the message was perfectly clear. They both knew what John had been going to say; in fact, they both knew quite a lot of things neither one of them had ever discussed. And as long as they kept things that way, they could both go on knowing absolutely nothing of the sort.

"Here," said John, and they paused in front of a darkened alley where Lestrade could just barely make out the dim silhouettes of people, low humps clustered together at the far end of the street.

"Not too close," said Lestrade. "We're not intruding, just… sharing the space."

They settled in a small area next to a set of concrete stairs, John flopping down with the confident air of a man who can sleep under any conditions, Lestrade leaning against the rough stonework wall and shivering as the nighttime cold crept through the thin material of his polo neck.

He wrapped his arms around himself, suppressing his body's reaction to the chill, but John had already noticed.

"Here, take the jacket."

Lestrade stopped him as he started to tug on a sleeve of the windcheater. "No. You've only got a T-shirt, are you mad?"

"Look at you, you're freezing."

"Yeah? And how long d'you think you'll last without anything on your arms?"

"You can't spend the night like that."

"Won't have to. We've been out here for ages; must be well gone midnight by now. Be up again in a couple of hours."

John shook his head. "I'm going to murder Sherlock, I swear."

"Well, don't tell me about it. Plausible deniabili… what are you doing?"

"As a licensed physician, making sure the hypothermia doesn't kill you before we can get his bloody 'insider information.'"

Lestrade blinked a few times, trying to decide exactly what level of protest would be acceptably blokey and masculine without actually pushing John away. Because John was warm, and his arms around Lestrade were far more comfortable than the frigid wall.

He gave up. No point.

"Er. Right, then." He rubbed the back of his neck, scruffed up the hair there, and leant back against the wall again, this time taking John with him. "Ah… good night?"

"Night, L'strade," John mumbled, already halfway to sleep.

Soldier, Lestrade remembered. John could probably fall asleep anywhere.

He settled in for what was left of the night, letting the penetrating cold of the tarmac creep up through the bones of his legs, feeling them go numb but too tired to do anything about it – too tired and too trapped by the grip of a compact army doctor.

Tomorrow, then. Tomorrow they could start making Sherlock's enquiries.