Sherlock's work gets them into a lot of strange situations, but up to his armpits in cute little orphans is not a place John ever expected to find himself with Sherlock.

They're sitting across from each other on beds in an orphanage dorm, surrounded by the small occupants of the room, under Sherlock's insistence that these children hold the key to solving their current case. If anyone ever found them here, they'd both go to prison for a thousand years, pointedly locked in with a large, tattooed serial offender suffering from chronic loneliness. But between their surprise entrance through a second floor window and Sherlock's general...Sherlockness, the kids are quite prepared to buy into the story that they're ninjas here to hunt down their rogue 'ninja brother.'

Between the crowd of urchins and Sherlock with his rakish hair and voluminous coat, John feels like he took a wrong turn into a Dickens novel. But the sight of Sherlock, sat on a low dormitory bunk with his long legs gawking up and a four year old in his lap playing with his pocket magnifier, is quite possibly the most heart-warming thing John has ever been privy to.

"He does sound like the fellow we're looking for," Sherlock says when the kids finish their multi-pronged description of the alleged quarry. He cocks a discerning eyebrow. "Would you say he looked like a ninja?" Their suspect, one Simon Stride, is a professional criminal who has seen more prosperous days. John commented to Sherlock two days ago that he had a certain ninja-like air. He'd practically got laughed off the stage at the time, but now look where they are. He ought to sue for copyright infringement. Or better yet, record this for posterity.

The children nod eagerly in response to Sherlock's question. John watches Sherlock's face settle in predatory satisfaction. "And what does Nurse Weaver say when he comes to speak to her?"

Guilty looks. "Oh come now," Sherlock cajoles slyly. "A ninja mysteriously appears to talk to your guardian once a fortnight, and none of you wonder why?" His eyes flick to the circulation grate on the left wall.

John follows the glance and laughs. "Tommy," he says gently, because Sherlock may be the cool one, but they both know who has the trustworthy face. "I think you might be able to help us, yeah?" He's learned a few things from his detective flatmate. Pale scrapes on the old wood floor are a giveaway that the bed nearest the grate has been moved repeatedly, and Tommy's a mousy, towheaded little bloke with a pout that reminds John of Harry. He knows trouble when he sees it.

Tommy's pout deepens. He could compete in championships against Sherlock. "Nurse Weaver's nice."

John nods encouragingly. "She doesn't deserve to be in trouble, does she? But Tommy, she could be in quite a lot of danger if we don't catch this man."

The children hold a silent powwow around the two grown men, communing in secret glances over what to do. John trades an amused look with Sherlock over their heads.

An accord is reached. Becca, the little black-haired ringleader of the gang, gets up to stare at John with a solemn expression. "He asks her about 'it.' Never says what 'it' is—does 'e, Tommy?" Tommy shakes his curly head. "But 'e allus wants to know she's still got it and it's safe. She wants 'im to take it back, but 'e says it's never time yet." She pauses, then adds, "Last time 'e asked, she was really scared. We wanted to chase 'im off, but she had the door locked on us." She points. "I was gonner electrocute 'im with that lamp."

John melts. If he could adopt…

"A fine mind, Becca," Sherlock praises. His eyes sparkle the way they do when he's inviting John along for an exciting evening of attempted suicide. "But why that lamp? This one is heavier." He waves at one on the other side of the room.

Becca shrugs. "This one's got a longer cord."

Sherlock has just fallen in love, John is pretty sure. "When we're done here," he promises, "I'll return and teach you how to pick locks."

John really ought to put the kibosh on that. He really should. But he's too distracted by the sight of Sherlock getting his scarecrow knees hugged by adorable rugrats.

And then by the smell of smoke. Sherlock's head whips towards the door the same time as John's, but John reaches it first. He doesn't have kids to disentangle.

The handle is warm. "Sherlock. He's burning the evidence."

Sherlock reaches around John to hold his hand up to the door and feel for himself. "That'd be us." They turn in place, assessing what they've got to work with. If it were just the two of them, they could get back out the way they came, over the rooftops. But John's just barely tall enough to make that trip. They look down at the fourteen meter-tall children who are staring up at them, trying to work out whether they're meant to be scared or not.

"Door's the only option," John says grimly. Sherlock nods and hurls himself to his belly. "Why aren't the alarms going off?"

"Disabled, obviously. Less warning for us." He strains to see through the crack under the door. The floors aren't level in a building this old. John hopes he can glean something.

While Sherlock does his thing, John rips the sheet off a bed, then passes it to Tommy. "Strip the beds and wet the sheets in the lavatory sink," he instructs the children, pointing to the attached water closet. "Then wrap them around yourselves. Keep a fold over your mouths and noses as much as you can."

As the scent of smoke grows thicker—quickly, alarmingly quickly—the kids are beginning to sniffle and shuffle. If they go into hysterics, he and Sherlock won't be enough to haul them all out bodily, but children are just like anyone else; something useful to do will help them keep their heads. "You all know what to do in a fire drill?" Most of them nod. "Good. Keep low when we go out. Smoke rises. Becca, you know the building layout?" Because Becca is among the most put-together of them right now, and they really do need someone who knows the building layout. She nods. "Right, you're with Sherlock. You tell us where to go. Hold hands, stick with us, call for help if you're afraid. How long's the fire been going, d'you reckon?" This to Sherlock, who's pushed himself up to his knees, texting.

"Five to ten minutes, depending on how wisely he chose his locations." He cocks his head, listening to the building's sounds. The way his eyes narrow bodes less than well. "He's set multiple fires. Of course. iNow/i we run into a smart one."

John makes a sound of disgust low in his throat. "Sherlock, these old buildings are fu-frigging fire traps." Kids, kids, don't swear in front of the kids.

Sherlock nods, thumbs flying. John doesn't complain on the off chance he's actually contacting someone useful, like Lestrade or the fire brigade. John gathers the children into a group to one side. When Sherlock shoves his mobile into his pocket and stands, they whirl as one to throw themselves at the door.

Wood cracks, then knocks them back. If John had less adrenaline in his bloodstream, that would probably hurt. Seeing as they've got better things to do than nurse their bruises, however, they set their jaws, back up a few steps, and hit it again.

It all but shatters under their shoulders, leaving them staggering through the sudden hole into a smoky, cinder-lit hallway. Sherlock curses, turning back and forth. Stride set fires at both ends of the hallway. They're going to have to run for it and hope the floor doesn't drop out from under them.

A wooden clatter behind them jerks them back toward the door. It's the falling shards of a broken chair, which at least solves the mystery of the durable door. "He planned this," Sherlock spits. "I'd have heard him if he'd placed that while we were in there."

"He knew we'd come here?" John beckons to the children, who come pattering cautiously out like soggy little ghosts. He scoops up one of the smallest, whose nerve is wavering.

Sherlock grabs two more, and Becca grabs onto his belt with a death grip. "He was after the children," he says blackly.

Something in John's head goes flat. "He'd best hope he's out of this building, then." He snatches up the longest remaining piece of the chair and passes it to Sherlock, who jostles the living package in his right arm till she grabs him around the neck and lets him free his hand.

John has more than once in his life had cause to be grateful for the erratic nature of fire. It takes a lot of work to burn down a building quickly and thoroughly. Stride might've planned on being more thorough if their presence hadn't thrown him off. They wind through a couple of rooms to get to the stairs, Sherlock prodding at the floor ahead of him.

They stop at the stairwell. "It's a chimney," John says in dismay. It looks alarmingly charred. Acrid black smoke is pouring up through the vertical space, and ruddy flickers stain the interior.

Sherlock growls something about fire codes, then his voice rings out over the sounds of the burning building. "Children! Copy me and hold your breath as long as possible!" Then he starts to deliberately hyperventilate.

John knows the technique. It hyper-oxygenates the bloodstream. A Pathfinder taught it to him when they were stuck in the field during a sandstorm. The children do as they're bid, their high-pitched panting rising up eerily around the two men among the roar of the flames.

After a moment, Sherlock sucks in one last deep breath and darts into the smoke. John herds the the children along after him, calling encouragements to them and bringing up the rear. He can't even see where he's going in the fire-shot murk. It reminds him uncomfortably of a night he'd spent being shelled in a makeshift hospital in the Green Zone. At least there he'd had oxygen for his patients. Here, the fumes—he really doesn't want to think about what's going into his lungs right now—claw at his throat and his eyes begin to flood over like a spring river. The little ones are coughing and wailing. Some of them try to filter clean air through their wet sheets.

The stairwell is outright on fire in some places. Sherlock leads by example, diving through licks of flame so fast that his clothes barely have time to smoke. John knows for a fact that Sherlock's had his coat treated with fire retardant, or he'd be even more worried than he is. They run down three flights of stairs, split by two landings. John feels his spine trying to crawl out the entire way with the anticipation of the ground going out from under his feet at any second.

When Sherlock's feet hit the ground floor, something does crack. He slams up against the wall, pushing the nearest children back with him. John nearly trips, convinced the stairs are about to go, when he hears it again and recognizes it as a gunshot.

"John!"

But John is already throwing himself down the final flight, sliding on his knees up against the other wall and firing round the doorway with a crackcrackcrack! The poor kids are screaming.

He waits for three beats of silence, then leans cautiously around the lintel. "I can't see him," he reports. The stairs come out on a large, emergency-lit common room that's cloudy with smoke, but it's in better shape than the upstairs. Things burn upwards, not down. Double doors lead outside at the other end of the roughly forty foot space. John leans out a touch more, deliberately presenting himself as a target, and then back when no one takes a shot at him. "He's either hiding or running. Go." He looks up at Sherlock, face stony. "I'll cover you."

Blue lights flicker through the curtained windows, casting a weird tinge into the smoke. Thank god, he did have the sense to call Lestrade.

"Becca!" Sherlock appeals to the little girl at his side. She looks up into that fierce mercury stare and her eyes snap from fear into focus. She nods, then looks at John, his gun at the ready and battlefield calm in place.

He nods back. "That's the police outside, Becca. We're almost safe. Help Sherlock get the kids out. I won't let anyone hurt any of you." And he won't. It's the promise he'd give Sherlock, if Sherlock would let him, extended to these little ones.

Sherlock might be smiling at him. John can't spare the attention to check for sure. But Becca definitely does—a tiny, brave little flick of her mouth before she turns to marshal her troops like a little general. "Hey! Everybody! Hey!" All eyes turn to her piping shriek. "Come on! Run after Sherlock!"

Sherlock ducks out with only the swiftest glance at John. The common room is a wide open space, broken up by furniture, supporting columns, and flimsy cubicle half walls. With Sherlock's legs, he could out-distance the kids in a flash, but he sticks right with them across the space, a tall and obvious target even in the poor light. If the shooter's still here, John is the only thing keeping his friend from being gunned down.

Crackack!

The shots come on top of each other, John firing the instant Stride pops over the cubicle walling. Sherlock jerks to the side, his forward momentum slowed by slamming open the front door, but the hitch isn't enough to be anything serious. John can afford to worry about it later. "Put it down or I kill you," John calls to the gunman in a smoke-ravaged rasp. He hadn't realized before just how bad he sounds. He missed Stride deliberately the first time. That's why the man didn't hit Sherlock. He was jerking away from the buzzing metal wasp John sent spinning by his ear.

Sherlock, the great git, is just standing there, holding the door open for the kids to clear out under his arm while he watches John perform. When he catches John's angry eye, he turns his face outside to shout, "Lestrade!" His beautiful voice is torn as ragged as John's. "There's a man with a gun!"

"Sherlock?! What the fff- Oh frack!" Ah. Lestrade's spotted the kids, then.

Stride stares at John. "I have a gun?"

Sherlock smirks at him, thin and sharp as a straight razor. "John's a good British citizen. I think you'll find he's far too well-behaved to carry an illegal weapon."

Which is sarcasm couched in bureaucratic threat—Mycroft has earned his Christmas card this year for rubbing off on Sherlock—but Stride takes it to mean that John's weapon isn't illegal.

And that is the moment when the stairwell in which John is still lurking caves in.

The thread of things momentarily gets lost in a caustic eruption of fumes and cinders and a swathe of hot pain along the right side of his body. John feels himself rolling, then grabbed and hauled upward by familiar arms that are as unsteady as he is. Oh Christ, Sherlock had to turn back for him, didn't he.

Everything around him has turned black, which is fine since he can't see anything anyway. There's stumbling and bumping and hands gripping hard and horrendous coughing and scraping pain on his palms, and finally awareness returns along with fresh air when John lands on his hands and knees outside. John finds himself hacking and wheezing, half-collapsed against Sherlock, who sounds like he just swallowed the building. Well. The half of it that didn't end up in John's throat.

He feels Sherlock's hand slide out from under his shirt, leaving behind the edges of John's gun digging into his left hip, tucked safely into his jeans.

There's an EMT headed their way, oxygen mask at the ready, but before she can reach them they're knocked flat by a swarm of hysterical children seeking their ninja saviours.

Then Lestrade is there on his haunches next to them, wearing the most bemused smile John's ever seen on his face while he gently shoos away kiddies and helps his consultants struggle up to sitting. It's not easy. They're still gasping and shuddering with the force of their coughs, spitting foul-tasting grime John doesn't even want to think about out of their mouths, and they seem to have picked up a bit of a smoulder, which Lestrade helps to beat out before it takes any notions. The moment that hands stop shooing her back, Becca entrenches herself in John's arms. He manages to spare a moment for pride at apparently becoming her favourite. Tommy, he notes, has lodged himself in Sherlock's snarled, ash-tinted hair.

Lestrade stops moving, sits back, and stares at the picture they make like he's never seen them before while he searches for his words. "Alright, you two?"

They both nod at him.

Lestrade nods back. "Right, then. This should be a good one."