Originally written for the BBC Sherlock Kink Meme! On page 31 of part XXI: "One day, Joan Watson trips and falls through a door that lands her in 221B. Except this 221B does not house the eccentric, madwoman Sherlock Holmes and her esteemed associate, Dr. Watson. No, this one has a very male Sherlock Holmes and Dr. Watson." I had quite a lot of fun with this prompt, although I was fumbling my way through things most of the time, honestly.

Joan stares up to the shelf at the top of the closet, furrowing her brow. "Sherlock," she calls, turning around, "what did you want me to do here?"

"Box on top shelf," Sherlock calls back from the kitchen. "Need it!"

"Well, then grab it yourself," Joan says, planting her hands on her hips. She's not going to mention that she can't reach the top shelf, but Sherlock already knows that anyway; Joan can practically see her smirking.

"Preoccupied; I expect you don't want me to burn down the flat," Sherlock replies. "There's a step stool somewhere around the flat, Joan, just pick it up and you'll be—oh, no, hm, that's interesting. Very interesting, indeed..." Sherlock's voice trails off, and Joan hears hissing from the kitchen that she's come to associate with certain acids. She huffs a sigh, lamenting the fact that she identifies acids with any sounds at all.

"Don't melt through the counters! Mrs. Hudson will have our heads for it!" Sherlock gives a distracted mumble in response and nothing more, and really, Joan just needs to stretch up and reach the top shelf now, so she can go to the kitchen and deal with this and not have Sherlock whine her ear off for not getting the damn box. She steps into the closet and stretches up onto the tips of her toes, grasping for the shelf and not bothering to hold the door open. Her fingertips scrape the edge of the shelf, she pulls herself up, and—

The closet door slams shut as a gust of wind trails through the flat, and she just barely hears Sherlock wonder aloud, "Why the hell are the windows all open?" as if she hadn't opened them fifteen minutes prior. The closet light flickers. Joan slides the box an inch, grunts, and turns to open the closet door. The first thing she notices is that the windows are all closed. The second thing she notices is that the flat reeks inexplicably of male deodorant.

The third thing she notices is the man staring at her and, God, is that her gun in his hand? Bloody hell. She wonders where Sherlock is; if anyone's laid their hands upon her, Joan refuses to be held responsible for her actions against them.

"Who are you?" the man asks steadily.

"I could ask you the same thing," she counters. Her hands feel far too empty without her Browning, and the ease with which he's holding her gun grates against her like sandpaper.

"No, you really couldn't," the man says, "considering this is my flat, and you've just stumbled out my closet."

As if someone holding her gun wasn't enough, he had to be insane. Lovely. "I think you'll find this is my flat, actually. My name's on the lease, right with my flatmate's. Binding legal contracts are difficult to contradict, gun or no." He raises an eyebrow, and she raises one right back. His hands are so steady that she might approve, were he not holding her at gunpoint with her own damn gun. "Now who the hell are you?"

"John Watson," he says cautiously. "Who the hell are you?"

Joan furrows her brow. It must be a coincidence, or some sort of ploy. "Joan Watson."

John narrows his eyes at her, looking just as confused, but he doesn't let up with her bloody gun, and she respects him a bit for that, although a real gentleman would give her a chance to take back her fucking gun and maybe break a bone or two. Or six. Or just whatever number feels right, she isn't picky. "Prove it."

"Excuse me?"

"Prove your identity."

Joan doesn't roll her eyes, but she's sure her desire to is clear in her tone. "Yes, of course, I carry about proof of identity whenever I traipse about the flat. Let me just get that out, then."

"Oh, this is interesting," a man's voice says from behind her, and Joan doesn't turn around, because there's (probably) only one gun in the room. Still, it bothers her that she didn't notice his entrance, and being trapped in her own hallway by two strange men, one holding her goddamn bloody gun, positively rankles. "John, why are you holding your sister at gunpoint? I'm supposed to be the terrible host, not you."

John furrows his brow, and Joan does the same. "She's not my sister, Sherlock." Joan's eyebrows fly up at the man's name, but John keeps talking. "I've no idea who she is. She introduced herself as Joan Watson, but obviously that's not right; it's just a lazy revision of my own name."

Joan scoffs. "No, that's what your name is of mine."

"Oh," the man calling himself Sherlock whispers behind her, and for a moment she feels electrified because that is the exact tone Sherlock uses when she's discovered something exciting. "Oh," he says again. He claps his hands. "Oh, this is fantastic, this is—" He grabs her by the shoulders and whirls her around, and she grabs him by the neck and goes to knee him in the groin, and he presses down just so on her shoulder like he knows her scar is there (but how could he?), and oh, God, that really burns, and her grip on his neck slackens and he wipes her hand off like it's nothing and looks at her.

His eyes are just like Sherlock's. Joan's hands fall to her sides uselessly, because there is no one, no one, with eyes like that. She has never met anyone other than Sherlock with eyes like that. She can feel him picking her apart as his eyes dart side to side, and he stares at her, and it's just like when she first met Sherlock. It's exactly like that. She feels more than hears her own breath hitch.

"Sherlock, what the hell is going on?" John asks. He's still got the gun on her. Of course he does, Joan thinks hysterically; it's exactly what she would do, if this happened to her and Sherlock, and... that is what's happening, isn't it? This is happening to her and to Sherlock, but to them as men, and that doesn't even begin to make any sense; maybe Sherlock's experiment went horribly awry and this is a hallucination caused by the fumes, maybe she's been drugged, maybe she dropped the box on her head and she's unconscious and this is some terrible dream—

Sherlock backs away, looking immensely pleased. He grabs Joan's hand and smiles. "Hello, Joan." He glances at John, still holding Joan's hand. "I have no idea. Isn't it wonderful?" John looks him in the eye, and Sherlock shakes his head, and Joan is completely thrown by this because she can read their expressions perfectly, because they look just like her own and her Sherlock's. Wait, her Sherlock's? She doesn't need to mentally separate them, because there is no way this man is the male version of Sherlock, and yet—

And yet his dark purple shirt is the same. His hair, his eyes, his facial structure, his long fingers and his pale skin. The way he holds himself, the way he looks and speaks and thinks louder than anyone else in the room. And the way John relaxes reluctantly, his body settling down in precisely the way her own would; the way he keeps his gun in his hand, because it has to be his gun, doesn't it? Because she's not in her flat at all, is she?

Sherlock looks between Joan and John, and his manic grin cements it. "Tea, then?"

John, despite his confusion and caution, moves steady sureness, clearly comfortable in a kitchen littered with half-finished experiments and fingers on the counter, a kitchen that Joan knows like the back of her hand, yet doesn't know at all. Watching him, it all seems so obvious, but it can't be. It shouldn't be. But his striped jumper is identical to the one in her closet, and his hair, and his height, and... He stretches up a bit to get mugs, and his left arm is hampered by what the voice in the back of her head says is a bullet wound acquired in Afghanistan, a wound that's left a nasty scar that still aches and makes stretching harder than it has a right to be and that's left him with nerve damage he doesn't like to discuss.

John looks at her, and she feels her knees go weak, because those eyes are hers, that guarded expression is hers. "Dash of milk," she answers before he can ask. "One sugar."

John does the same for his own tea. The third mug gets two sugars, and Joan knows it is for Sherlock, and Joan knows he'll only drink a third of it to appease John and then leave the rest to get cold until John pours it down the sink right before bed. She clutches her own cup of tea like it's the only rock in a roiling sea, and hell, what an awful rock to choose; it's just as likely to get swept away as she is, and then all of her tea will be full of seawater, won't it? Joan drowns hysterical laughter in her cup.

John puts his cup to his lips, and Sherlock, who has been looming in loud silence for the past few minutes, finally bursts. "How did you get here?" he demands.

"Closet," Joan says. "Door shut, opened it, walked out here instead of my own flat." She sips at her tea, her perfectly made, familiar tea, and something in her threatens to crumble, so she reinforces it with steel and sits up straighter than before. "If Sherlock hadn't made me try to get that box—"

"There's another me?" Sherlock asks happily.

"What box?" John asks, much less happy.

"Box on the top shelf. She needed it." Joan drains her cup, and sets it on the table next to something that looks like a human eye in a bowl. She looks at Sherlock, and frowns. "I wouldn't call her another you. It's more like you're another her, really."

"Wonderful," Sherlock says.

"A box like this?" John asks, holding up a cardboard box; she hears clinking, and presumes it's full of glass. Probably chemistry equipment. She notices John finished his tea almost immediately after she did.

"I don't know. I never managed to get it down," she admits. "The wind blew the door shut before I could grab it. Sherlock left all of the windows open in the flat."

"I closed the windows because it was getting drafty," John says. He looks her in the eye, and Joan can pinpoint the moment he has the revelation she had, because his shoulders relax and tense again just as hers did, his dark eyes pierce into her own, his brows draw together for just a moment before his expression falls. She knows he's hit the same odd acceptance she has. She just knows. "So... Joan."

"John." She nods to him.

"...right." He nods back.

Sherlock is looking between them like he's discovered the mother lode. "Tell me more about your version of me."

"...and so I shot him," Joan says, "because otherwise that idiot would have taken the pill and killed herself, and I wasn't about to look for another flatmate."

John smiles, nodding in commiseration. "He did the same thing, of course. Sherlock's always trying to prove he's cleverer than everybody else."

Joan rolls her eyes, taking a sip from her third cup of tea. "You're telling me. Always getting into fights without me, refusing to open the door when she breaks into another bloody flat—"

"Yes, and then getting so touchy when I'm bothered by that—"

"I don't like the turn this conversation has taken," Sherlock says, looking between them like he's discovered a bomb. John and Joan ignore him with the same turn of their shoulders, and lean in closer to talk about Sherlock's annoying habits that apparently transcend space, time, and gender. "We should get you back."

"Feel free to figure it out, then," Joan says.

"It'll be a lovely mystery for you," John says. "Does your Sherlock do the thing with the nicotine patches?"

"If I hear the words 'it's a such-and-such-number patch problem' again, I will flay myself. It's like she wants to die, it's infuriating."

Sherlock leaves the kitchen to investigate the closet while John hums in agreement.

John looks at Joan, really looks at her, while she speaks. They both finished their tea long ago, the cups now soaking in the sink beside beakers and flasks, but they're still chatting in the kitchen like a couple of old hens. It isn't something he's really used to, but it feels natural, with Joan. He supposes it makes sense; they obviously have a lot of common ground, being alternate versions of each other and all. Still, for all their similarities, he's noticed some differences.

The clearest is, of course, that she is a woman. She's wearing a sweater covered in Scotties that John remembers seeing when he bought his black cat sweater. It fits her perfectly, hints at the curves of her body, and his eyebrows draw together because in a way it's... sort of his body. But it's not. It's his female self's body. And his female self is not him, she's just a lot like him, having generally led the same life, but not.

He's only distracted because it's strange to see his female counterpart, nothing more.

Right.

"I'm sorry, what?" John asks, realizing he's missed the past few sentences. Joan is silent, looking at him like she can read his mind, resting her chin on one hand.

"It is a bit odd, isn't it? Don't worry, I've been distracted by pretty much the same thing." Joan's wry smile is achingly familiar. "Never thought I'd see myself with stubble."

"Never thought I'd see myself with shoulder length hair." John smiles back. "It's a lot to take in."

They smile at each other like that for a few moments, taking in details that are at once old and new, and with anyone else John is sure he would feel quite awkward. The speculation comes to a halt when Sherlock returns, looking annoyed and excited simultaneously, holding his cell phone. "Lestrade has a case." He looks at John, then Joan, and frowns. "You're a doctor," Sherlock says to Joan.

"Yes."

"You go on cases with your Sherlock." Joan nods, and Sherlock nods back. "All right, you can come. Take John's other coat." He leaves the room, texting Lestrade, and John shares a half-pleased, half-exasperated grimace with Joan that is well-practiced on either end.

Sherlock gazes out the window of the cab as John and Joan chat quietly, probably talking about themselves some more. One of John's thighs is pressed against Sherlock's, and the other is pressed against Joan's. He wonders if John has acknowledged his latent attraction to her yet, and if he has, whether or not he's twisted himself up over it.

John lets out the same little laugh he uses when Sherlock does something he considers endearing, and Sherlock restrains a smirk. He's noticed it and denied it, then. Typical John.

He doesn't judge John for his attraction, not at all. Perhaps it's narcissistic in a way, but Sherlock considers that unimportant; John should appreciate himself more anyway. Besides, Joan is just John's type (blonde, short, laughs at his jokes), but with the very welcome twist of not being completely dull. Sherlock finds her physically attractive in many of the ways he finds John attractive, although her hair is longer, her chest is rather more developed, and her jaw is softer. They have the same nose, the same eyes, the same tan and tired look, but it's all wrapped up in something hard yet feminine, and it is pleasant.

Were he to meet his female counterpart, Sherlock thinks he might have a similar reaction, although it is equally likely that they would despise each other; guessing at the outcome is useless, as he lacks data, so he dashes his theories away and focuses on how both John and Joan flirt with their hands, and their shoulders, and their laughs. Joan rests her hand on her thigh, the side of it just barely touching John's leg, and Sherlock estimates that one or both of them will have a sexual identity crisis within the next eight hours, or fewer if he solves this case quickly, which he will. He's already halfway to the conclusion as it is.

Joan brushes her hair behind her ear, and John's hands fall down to his thighs, one brushing against Joan's hand while the other presses against Sherlock's leg. Of course, Sherlock thinks; John is most likely trying to reassure himself of his attraction to Sherlock, and using it to explain his feelings. Sherlock drops his hand down to cover John's, swipes his thumb over John's knuckles, and watches Joan's eyebrows twitch upward in the reflection on the window. She shrugs, leans over to tell John some kind of joke, and they laugh together again.

Sherlock wonders if his female counterpart is in a relationship with Joan. It seems probable; almost everything else has been mirrored thus far, and she is evidently comfortable with their handholding. Then the cab stops, and he pushes all of those thoughts away as he opens the door, because now he's on the case.

As she barrels through the narrow alley, dodging garbage bins and splashing through puddles, Joan wishes she had her gun. She would feel a damn sight better if she had the weight of it in her hand as she chases after Sherlock, who is chasing after an apparent killer, who is chasing after some faint glimmer of hope that he'll evade capture, and who has left behind a very jarring trail of dead women. At that thought, part of her reconsiders the gun; she's not sure whether she'd like to shoot him or to bash his teeth in like he'd done to four of his victims.

The alleyway is constricting with the four of them packed into it, but it hardly matters. Sherlock is gaining on the man, and Joan doesn't have to glance at John, barely has to spare him a thought, before they're both speeding up in tandem. Sherlock is brilliant, and they both know by now that he can care for himself, know how strong he is, and yet there is a jolt in the pit of Joan's stomach, something that tugs sharply at her insides and propels her forward, and with John beside her it's almost like she's faster, like she's competing with him, competing with herself—

She and John overcome Sherlock, then slam into the suspect simultaneously, driving him mercilessly into the cold asphalt. Joan digs her knee savagely into his back, and when she looks up, John's face is carved from steel, and she thinks, "oh." He meets her eyes, and gasps shortly before they both come back to themselves, flipping the man over. It doesn't take a medical expert to see he's twisted his ankle, and Joan decides to worry about the nasty thrill of pleasure that gives her later, when she's feeling less like she's been electrified.

Sherlock strides up, oozing pleasure and smugness and excitement, and Joan stands, shoving her hands into the pockets of the brown coat she borrowed from John, focusing on the bits of lint between her fingers as she watches Sherlock grill the man on the ground. He can't be more than twenty, and he's curling up around his wound, groaning and sobbing like the world is going to end just because he's sprained his ankle.

"Are you all right?" John asks, walking around to meet her.

Joan looks at him evenly. "I'm fine." She wonders if her pupils are as blown as his are.

Probably.

He lets out a shuddering breath, and her lips twitch, and they turn away from the man on the ground because it would be awfully inappropriate to giggle in his face, wouldn't it? Their shoulders brush together, and she thinks, "what the hell?"

Sherlock smiles down at Lawrence Berkins, despite his being a man who deserves no smiles at all, because he can tell the exact moment when Joan leans over to kiss John without having to look. Joan sighs, and John's breath hitches in his throat; he makes an eager little noise, and from the rustling of his coat Sherlock is fairly sure he's reaching up to touch Joan's hair, although it is also possible he is touching her neck. John enjoys touching people's necks.

Berkins whimpers up at him pathetically.

"Be quiet," Sherlock snaps. He stands, rests one foot directly on Berkins' sprained ankle, then pulls out his phone to text Lestrade—but first, he turns, and snaps a photo of Joan and John kissing. The sound of the shutter pulls them back to Earth, and they both look at him sheepishly, John opening his mouth to stammer out some unnecessary apology. "Six hours and twenty-seven minutes!"

John halts around a half-formed word, frowns, then tries again. "What?"

"Six hours and twenty-seven minutes since we left the cab, which makes it six hours and thirty-three minutes since I predicted this would happen, and seven hours and twelve minutes since I deduced you were attracted to one another." He snaps a photo of Berkins and sends it to Lestrade, along with their location and a reminder of Sherlock's greatness.

"You're not upset?" John asks. Joan's expression matches his, a charming mixture of perplexity, guilt, concern, and what Sherlock can identify as attraction only because John has been generous enough to teach Sherlock what that looks like when it's directed at him. He straightens up, grinding his foot downward enough that Berkins won't be getting up to hobble away anytime soon, and arches a brow.

"Should I be?" He looks between them. "If she was just any woman, I would be very annoyed, yes, but she is sleeping with me in an alternate universe, so I really can't hold a grudge."

Joan's face goes red, and when John glances at her, he goes red as well. Sherlock's lips twitch, nearly becoming a smile, because that is another thing he has gotten correct while working with insufficient data, and really, he is so good at this. He pats both of them on the shoulder, then strides through the alley to the street. "Lestrade will be here soon; I'd rather not get questioned, although if you're both interested in catching flies with your mouths, I will do my best to be sensitive regarding Watson traditions." After a pause, they fall into step behind him, their footfalls synchronized, and Sherlock smirks. Yes, he is very good at this.

"Taxi!"