It starts with a dance. It ends with blood. There is not so much distance between the two as one might think. Most things worth doing ultimately require either blood or tears and this one will extract both. But that is not for a long time yet. This is just the beginning, and right now there is only dancing.

Countless women, exotic birds in glittering gowns every colour of the rainbow adorn a dance floor, in a house old enough and large enough to have its own ballroom. Men, elegant magpies in nearly identical coats and tails, attend them, twirling them round, showing them off, moving in step with them. Other men and women, likewise attired, line the sides of the cavernous room, admiring, eating, drinking, chatting gaily like a flock of finches, flitting about from one conversation to the next, never settling.

Sherlock Holmes and John Watson do not dance and do not flit. They stand, a little apart, in an out-of-the way corner near the canapés, indistinguishable from the rest by dress yet with a well-defined chasm of mental space between themselves and the rest of the partygoers. Or perhaps that is just Sherlock, as John looks rather like he is enjoying himself, despite his lack of participation.

"So, explain to me again what we're doing here," he asks his glowering friend cheerfully, sipping his second…third…glass of good vintage champagne.

"Mycroft," Sherlock growls, as if that is adequate explanation.

"You never do what Mycroft wants. Out with it."

"This is the annual charity gala he hosts with his…lady companion."

John nearly spits out his champagne. "Mycroft's got a lady companion? Mycroft's got any companion?"

"Horrifyingly, yes. They've had a long-standing arrangement for many years."

Of course, an arrangement. The Holmes men certainly wouldn't go in for anything so unappetizingly normal as an actual relationship. Or a marriage. "That still doesn't explain how he managed to get you here."

"Apparently the Lady de Corataine has been feeling rather put out that none of his family ever attends the event. In the interest of domestic peace he requested that I come this year."

"Uh huh. And what did he say would happen if you refused his request?"

"I was to be put on every terrorist watch list from here to Istanbul, as well as anonymously reported to HMRC for an audit."

"Have you ever even done your taxes?"

There is no response.

"I won't even go into how profoundly screwed up it is that your family's version of 'please come to my party' involves illegal threats and tax evasion. That takes care of you, what about me?"

Sherlock digs in his pocket for a crumpled invitation, embossed on expensive stationary. " 'Mister Sherlock Holmes & Doctor John Watson are cordially invited…' " John reads. "Christ. He'll be hyphenating our last names next."

"Hope springs eternal in my brother's ample bosom," Sherlock says darkly.

John coughs and changes the subject. "So, this is Lady…de Corataine's estate, I'm guessing… Impressive."

"No."

"Not impressive?"

"Not her house."

"Oh. Well, then whose house are we in?"

Sherlock looks uncomfortable and stares at the parquet floor.

"No! You never did!" John had figured out that Sherlock's family was well-off a long time ago. One didn't get a taste for custom suits, £2,000 coats, or hundred year old bottles of wine from a middle class upbringing. Still, this went beyond well-off and into the aristocracy. "You grew up here? This is out of a Jane Austen novel!"

"Mycroft isn't the first Holmes to control the dealings of several major world governments. Money and land tend to be a side effect of such things. Please, John, I would really prefer not to discuss it."

John decides Sherlock is suffering enough for one evening. "Alright, but we are talking about this later."

Sherlock sniffs and goes back to observing the crowd. After a few moments he perks up visibly. "Oh, interesting," he breathes.

"What?"

"Nothing, John. I'll…be right back."

"Enjoy yourself. I'm tired of standing here. I'm going to go meet some people."

Sherlock looks askance at him. "People? What people?"

"Any of the two hundred other people in this room, Sherlock," John replies with a tolerant sigh. "Maybe I can find some old money of my own."

Sherlock is unamused and slips into the crowd without a word. He works his way silently to the other side of the dance floor, carefully watching a much-decorated older man talking in a group near his brother. He goes over, introduces himself and speaks to the man briefly, emerging from the conversation with a smug smile. He glances back and spots John engaged in conversation with several women, one quite a bit older than him, all wearing off the shoulder dresses and laughing – laughing! – at something he is saying.

Sherlock makes a quiet noise of disgust and goes to present himself to his host. Might as well get it over with.

Mycroft is insufferable while his companion looks distant but pleased. Sherlock kisses her hand absently and she remarks how charming Mycroft's baby brother is, so much more than he's described.

"Give it time, my dear," Mycroft says dryly. "Nice to see you, Sherlock. Where's John?"

"Flirting," Sherlock says grimly, flicking his eyes briefly across the room. "Mycroft, your ear?"

"Excuse me," Mycroft tells the Lady, and steps aside with Sherlock who whispers something to him with barely restrained excitement. "Excellent. I'll take care of it straight away. Do try the dessert."

When Sherlock reaches John he still has three women, all out of his league, vying for his attention. Sherlock supposes it is the formalwear – John looks good in a tux. Sherlock dispatches his friend's hangers-on with a quick, icy glare and, snatching an entire tray of delicate pastries off a waiter, collapses into a chair next to John.

"Thanks for that," John says dryly.

"Oh, like you were going to get off with a countess. I did you a favour. Pastry?"

"Countess? Well, might have done, you never know." Sherlock gives him a look that says that he most certainly does know, and John ignores him. "And why do you suddenly look so pleased with yourself?"

"Oh, I just informed my brother that Sir Robert over there has been funnelling Ministry of Defence funding not to the domestic anti-terrorism project he's been appointed to supervise but to a rather lavish vacation home in southern Spain. And a rather young Spanish gentleman who attends him there."

"I'm quite certain your brother did not invite you to this party so you could out his guests as embezzlers and adulterers," John tells him, rolling his eyes. There is a pause. "No, that's exactly why he invited you here, isn't it? One day you will have to tell me about your childhood…it must have been so carefree."

Sherlock snorts and turns his attention to the dance floor and sighs. "Tedious. You dance, John?"

"I have. I can't say it went particularly well. Not really my area."

"Nonsense, even these vapid, empty headed, inbred ninnies can manage it, I'm sure you could probably pick it up." John looks doubtful, which Sherlock appears to take as a challenge. He discards the pastries and stands, put-upon, and holds out his arm. "I'll show you."

John looks at him, mildly horrified. "You've got to be kidding."

"Absolutely not. I was classically trained for this type of mind-blowingly purposeless activity. I really shouldn't let it go to waste."

"You're testing me aren't you? This is a test."

Sherlock sighs. "John, I am bored. We're at a dance. The only thing to do is dance. Think very carefully about the list of things I might decide to occupy myself with at a party like this if I have no one to dance with before you make your decision."

"This is blackmail."

"Technically, it would be closer to extortion. Come on, it's an easy waltz, you'll pick it up in no time."

John sometimes wonders if he is actually capable of saying no to Sherlock. If he is, it appear he's not going to find out tonight. For no reason he can think of, he allows himself to be led to the dance floor. "Arm on my shoulder, hand here," Sherlock orders, taking his hand and placing the other firmly on John's back. "Try not to lead. Let's give Mycroft a thrill."

John is aware of a few stares and whispers around them, but not as many as he had feared. Not that it matters. He's not likely to see any of these people ever again, and attempting to maintain a sane, heterosexual identity around Sherlock has proved to be fruitless. He gives in, and tries not to be too clumsy.

Sherlock keeps his body a respectable distance from John's, but sweeps him along smoothly, telegraphing every step. He's right, it really is simple when your partner knows what he's doing. And Sherlock definitely knows what he's doing. He dances with an easy, careless grace, like he's been doing this his whole life. All John has to do is follow. That's all John ever has to do, really.

Sherlock's suit is perfectly tailored, and orders of magnitude more expensive than John's rented one. It accentuates his tallness, nipping in perfectly at his slender waist while managing to highlight his broad shoulders. His hair is tamed for once, curls shiny and neat against his head. He looks like the product of a bygone era, suave and polished. At some point John stops thinking about how uncomfortable dancing with his flatmate in front of society elite is, stops worrying about people talking, and sees only him as they glide across the dance floor, inches away, touching, and yet somehow still unreachable.

"Not bad, John," Sherlock whispers. "But stand straighter."

John obeys and feels the change immediately, the smoothing of the rough edges of his steps as they twirl and spin, tails pinwheeling behind them. He feels caught up in an enchantment, like none of this is real, like they exist alone in a private bubble and everyone else is just decoration. He suddenly feels a little lightheaded and misses a step. Sherlock pulls him a bit closer, arm like iron around him, holding him up.

Sherlock's eyes are half closed, listening to the music, and he wears a small smile of contentment on his face. He seems happy and, moreover, peaceful, which is not an emotion John has learned to associate with him. They are too close now, John can smell him, can feel the blood pumping into his hands and his warm breath on John's cheek. It's too intimate, changing the dance from a simple quirk of Sherlock's into something that might have another meaning, and it spooks John, brings him back to the reality of where he is and what they have been doing.

Before John can balk, the song ends, the spell is broken, and Sherlock releases him and bows, slightly sardonically. "Well done. Now you can try that with a countess. Excuse me." Before John can respond, Sherlock vanishes.

John feels his face is hot, and must be quite red, and exits the dance floor as quickly as propriety will allow, downing two more glasses of champagne on his way. He has no idea what just happened, and he spots Mycroft making his way purposely towards him. Absolutely not. He is not going to have that conversation with Mycroft, not now and preferably not ever.

He leaves the ballroom and after a few wrong turns in the huge mansion, manages to find an exit, though it's not the one they came in. He is in some kind of courtyard. There are stables in front him. Actual stables, with, he imagines, actual Thoroughbred horses in them. It's not hard to find Sherlock, standing behind the stables, smoking.

It's a sharp November night, full moon out, and his breath turns to a cloud in the air. John approaches Sherlock with studied nonchalance, trying to hide his awkwardness. "I suppose you ride, too."

"Of course I ride," Sherlock snaps. "I ride, I dance, I play polo, I speak French, I choose wine, and I know the difference between an ascot and a cravat." His voice is surprisingly bitter.

"I would have thought you would have deleted all that information," John says. "Polo's not much use to a detective."

"Don't think I haven't tried. Unfortunately, some memories are rather stubborn. The last time I was on a dance floor…" he trails off, shaking his head. "It doesn't matter."

"Seriously, Sherlock, what was that? Were you just trying to fuck with people? Experimenting to see what I would do?" He does not say, Or were you just jealous and trying to mark your territory in front of everyone?

Sherlock glances at John. "Neither. I felt like dancing. I haven't done it in a long time. You were the only person there who was not completely odious to me. It made sense at the time. Did I embarrass you?"

John sighs, and snatches the cigarette out of his hand, tossing to the ground. "No, Sherlock. It's fine. You're… quite a good dancer."

"I know," Sherlock says miserably.

"Well, none of us can escape our upbringing, not really," John says, patting him on the arm carefully. "Family parties always seem to bring out the best in people. You're smoking, I'm drunk…let's go home before someone ends up in tears, shall we?"

Home. John says it without thinking, then regrets it. Technically, Sherlock is home. What a home life this must have been, too, so privileged. And yet Sherlock has done his best to disassociate himself with nearly every aspect of it.

Sherlock doesn't seem to notice the slip, and gives John a half smile, ruefully. "Wise as always, John," he says, wrapping his coat more tightly around himself. "Here, if we go this way we can avoid going through the house."

John follows Sherlock through dimly lit, perfectly manicured gardens. He doesn't believe for a second asking him to dance represented only a simple whim on Sherlock's part, but knows he's not likely to get more than that out of the detective unless he decides to share. It doesn't matter, really, just one more thing to add to the strangeness that has become his life. At least, as long as he can avoid thinking about how quickly his heart was beating when he was in Sherlock's arms.