## Knot Theory

### Chapter Text

Act 1: The Recognition Problem

The basic problem of knot theory, the recognition problem, is determining the equivalence of two knots.

Before:

It begins with a phone call from Mycroft.

Sherlock doesn’t answer it, of course. He being busy with an entirely fascinating experiment regarding the hydrolysis of phosphate esters, and Mycroft being Mycroft. He does take a moment to throw one of John’s jumpers (discarded on the sofa the night before) over it so its flashing lights do not interrupt his concentration.

As such, when John returns home that evening—greeting the mongrel and kissing Sherlock chastely on the cheek in an instance of domesticity that is so saccharine as to be almost painful—he takes one look at the missed calls notifications on Sherlock’s phone after retrieving his jumper and spectacularly overreacts.

“Sherlock! Would you please call your brother?” John’s hair is lightly mussed from the wind outside (he hasn’t taken the time to have it trimmed to its typical military shortness, and it flops adorably over his ears), and he looks adorably flustered.

Sherlock glances up briefly from the notes he is taking on his laptop to give his flatmate an arch look. “Not interested.”

“I’m serious,” John says. Seriously. “Or text him, if you’d rather.”

“I don’t see why it’s any concern of yours.”

“It’s a concern of mine when he gives up on contacting you and starts calling me instead,” John says, running a hand through his hair in exasperation. “And since it looks as though he’s already tried fifteen times today, I imagine the harassment is going to start in the very near future.”

“You’re overreacting.”

Fifteen!

On cue, John’s phone beeps, and Sherlock becomes the recipient of a rather aggrieved look.

“Don’t be melodramatic. You don’t know that it’s him,” Sherlock says.

The phone beeps again from where it rests charging on their end table. Gladstone trots over to sniff at it curiously, and John’s eyes narrow.

Sherlock sighs. “I’ll see what he wants,” he gives in grudgingly.

After all, it is a hallmark of relationships that often compromise is in order. Sherlock is amenable to the idea, so long as John doesn’t come to expect it to be a frequent occurrence.

**
Day 1:

“You want me to chase down a truant child?” Sherlock injects his voice with just the right amount of sneering disdain to relay precisely what he thinks of the request. And because it’s a tone his brother has always found intensely annoying.

Mycroft’s jaw twitches oh so slightly—a reaction only one who knows him well would notice—and Sherlock smirks triumphantly as he shifts in one of the ancient, wooden chairs that his brother seems to insist on populating his office with. The resulting creak echoes loudly in the small space.

“I want you to locate a missing boy,” Mycroft corrects. “The missing son of a Duke, to be exact. And I highly doubt that truancy was involved, given the particulars of the case.”

Sherlock takes the bait, though not before he subjects his brother to a long, hard stare at the obvious manipulative tactic. “What particulars exactly?”

“The boy, ten-year-old Lord Saltire, disappeared from his room at his preparatory school in the middle of the night two evenings ago. Based on the contents remaining of his wardrobe, he was fully clothed but took no additional attire with him. There is also some indication that he climbed down the ivy to reach the ground from his second-storey window.”

Sherlock forces another creak out of the chair. “I fail to see anything of interest in those particulars, Mycroft.”

“We also believe the boy took possession of one of the other pupil’s bicycles,” Mycroft continues, giving Sherlock a disapproving look at the interruption. “The bicycle was found missing the morning after the child’s disappearance: blue, with a patched tyre.”

“Clearly the boy is a budding criminal genius. Why have you bothered me with this, exactly? Your favoured brand of sadism is usually more subtle than this.”

“The boy’s German instructor is also missing. A man called Heidegger.”

“How scandalous,” Sherlock replies blandly, wringing another tortured sound from his chair, and for just a moment, Mycroft looks truly pained.

“Lord Saltire’s father, the Duke of Holdernesse, believes that kidnapping is involved, though as of yet there have been no ransom demands. He is estranged from the boy’s mother; however, their separation sounds as amicable as is possible under such circumstances. She is currently in the south of France.”

“Oh, honestly, Mycroft,” Sherlock says, throwing his head back over the edge of the chair and pushing himself into a spin out of sheer boredom. “The boy ran away to join his mother. Obviously. He’ll be found in a day or two curled up on bench at a train station and rained with sweets while he waits for his father to come fetch him.”

Mycroft’s face remains gravely composed. “Without a doubt, that is the most preferred outcome. But it is not one William, the boy’s father, is willing to assume will occur. Nor am I.”

Sherlock peers at his brother. “The Duke. He’s a friend of yours?” The word ‘friend’ sits oddly on his tongue when applied to his brother. He has never known Mycroft to have people in his life beyond assistants and sycophants. And Sherlock, of course.

“He is a valued acquaintance,” Mycroft confirms. “We were at school together for a time.”

Sherlock makes a noncommittal sound, pushing himself through another two rotations in the chair while considering the request. He doesn’t have any other cases going at the moment, and John had mentioned something about extra leisure time in the near future due to the surgery being closed for some type of renovation or another. Sherlock hadn’t paid attention to the specifics, beyond the noteworthy fact that John will be freer over the next week or so.

And should the boy have somehow managed to leave London, a short trip to France with John would not be in any way a hardship.

“Text me the information,” Sherlock says, abruptly climbing to his feet.

Mycroft smiles approvingly, though Sherlock finds it is less infuriating than normal, and waves a file folder meaningfully in Sherlock’s direction. “I took the liberty of having copies printed for you.”

Sherlock takes the folder with a grimace. “Hard copy. Do consider joining us in the twenty-first century, Mycroft.”

“I will take your suggestion under advisement,” his brother replies solemnly, which is the closest he ever comes to humour.

Sherlock pauses before he reaches the door. “Given your connection to the Duke, I would have thought you’d have handled this yourself.” The question is implicit, and Mycroft doesn’t pretend to misinterpret.

“Unfortunately, I will be leaving the country this evening.”

“International travel? You?” Sherlock grins at his brother’s obvious discomfort.

Mycroft glares at him sourly. “It is unavoidable. I shall no doubt be out of contact for several days.”

“If you yourself are unavailable to assist the Duke, you could have put your best people on it,” Sherlock says, raising an eyebrow.

“I did,” his brother says crisply, already returning to the documents lying in orderly piles across his desk.

The rush of pleasure is unexpected (though agreeable), and Sherlock leaves quickly before his brother can manage to shock him for a third time.

**

The Duke answers the door himself when Sherlock arrives.

He’s a large man: broad-shouldered and beginning to carry a bit of a paunch. His hair has thinned considerably on top, but his complexion is surprisingly youthful.

His eyes are red-rimmed.

“Holmes?” he asks, voice soft. At Sherlock’s nod, he steps back and allows the detective entry into a cavernous entry hall. Strangely cavernous, really, and appearing even larger due to the absence of any furniture or decoration.

“I’m in the process of redecorating,” the Duke explains at Sherlock’s questioning look around the profoundly empty entry. “My wife-, my ex-wife, requested the majority of the furniture when she left. Unfortunately for me, she was the one with all the taste. I have absolutely no idea what to put in here.” The Duke stands for a moment and surveys the room, as though taking stock of the amount of space he needs to see to filling.

“There are still a couple of chairs in the library. We can talk in there. At least it will be somewhat comfortable.”

The library does indeed contain chairs: two hand-carved antique armchairs in dark, burnished leather crouching heavily near the cold fireplace. The library does not, for whatever reason, contain books—the shelves empty and gleaming from a recent cleaning—but Sherlock decides that is a mystery he can afford to let lie.

“You’re Mycroft’s brother?” the Duke asks as he settles himself slowly into one of the chairs. Sherlock does likewise.

“I am,” Sherlock confirms, steepling his hands as he leans against the backrest. It’s surprisingly plush and comfortable, and he settles himself against it with subtle relish.

“I didn’t realize Mycroft had a brother,” the Duke murmurs. “We were at school together, but we didn’t know one another particularly well. I suppose he just might not have told me. Same parents?”

If the Duke is taken aback by Sherlock’s abrupt entry into the topic, he makes no sign of it. “Very little, I’m afraid. I was away on business when it happened.”

“Where were you?”

“Glasgow,” he replies, leaning forward to reach a small table set to the side of the chairs and removing a pipe. The smell of the loose tobacco prickles in Sherlock’s nose, and he abruptly wants a cigarette. Or a nicotine patch.

“I have business interests there,” the Duke continues.

“How did you learn he was missing?” Sherlock asks.

The Duke doesn’t answer immediately, instead filling his pipe and lighting it with a ponderous slowness. He takes a draw of the smoke, but he doesn’t seem to particularly enjoy it.

“James. My personal assistant. He called me.”

“James?”

“James Wilder.”

“And how did he know of the disappearance?”

“The headmaster of Quentin’s school, Huxtable, came by looking for him when they realized he wasn’t in his room.” Sherlock notices that the man’s hands are trembling very slightly as he holds his pipe, and—perhaps sensing his regard—the Duke lowers them to rest on his thighs.

“He was here then? James?” Sherlock asks, tilting his head forward as he stares at the other man. John told him once that the mannerism is off-putting and occasionally nerve-wracking to those he’s interviewing, and Sherlock had told John that that was the entire reason he employed it.

Mycroft’s school chum or not, the Duke is hiding something.

“He occasionally stays the night at the house to keep an eye on things when I’m away,” the Duke explains. He begins to worry the pipe between his fingers. Like all of his movements, it is done slowly and deliberately, but Sherlock knows a nervous fidget when he sees one.

Sherlock smiles encouragingly at the Duke to go on. It’s entirely insincere, but the other doesn’t appear to realize his pretence.

“He’s been my assistant for well over a year now.” The Duke says, clearly feeling compelled to fill the silence. The fact that he chooses to continue to discuss his assistant is interesting. “He’s been excellent. A Godsend.”

“It sounds as though you trust him a great deal,” Sherlock says noncommittally. Rather than answer immediately, the Duke takes another puff from his pipe, and Sherlock smiles again. This time the expression is authentic.

“Sir?” a voice—young, masculine—reverberates through the empty house and comes to rest in the library.

“In here, James,” the Duke calls in response. He appears to be reaching the end of his endurance for prevarication, and the relief in his tone is more obvious than it would have been at the start of the interview.

James Wilder is young—in his very early 20s—as large as the Duke, and very handsome: a fact with which he is evidently extremely comfortable, if the wide, charming smile he adopts as he enters the library is any indication.

“James Wilder,” the arrival says, holding out his hand welcomingly as Sherlock rises from his chair.

Sherlock takes it and returns the expression with a charming smile of his own (he has been practicing one with a shade of bashfulness that he finds particularly effective).

“Sherlock Holmes,” he returns.

“The brother of a former schoolmate of mine,” the Duke explains. He remains seated for the exchange, looking increasingly ill at ease. “A private detective.”

“Really? A detective?” James continues to smile engagingly, but the expression no longer meets his eyes: a light hazel. Like the Duke’s.

“A consulting detective, actually,” Sherlock says, dropping his eyes as though self-conscious. “My brother asked me to see if I can help in the search for your employer’s son as a favour to him. We’re very close, my brother and I,” he adds earnestly, on a whim.

“What brothers aren’t?” Wilder asks. The question is presumably rhetorical, but the jealousy behind the words would be readily apparent to even a casual observer, and from the corner of his eye, Sherlock sees the Duke stifle a wince.

“If you’ll excuse me for a moment,” the Duke says, rising to his feet and looking blankly around the room. “I need a glass of water. Would you like some as well, Mr Holmes?” he asks belatedly.

Sherlock declines, and the man leaves the room as though he’s fleeing.

“I’m just so surprised that Quentin would have run off,” Wilder says, taking the now vacant second chair. “They said he stole one of the other pupil’s bicycles? That’s not like him at all. But I suppose I don’t know him all that well, really.”

“Do you have any idea where he might have gone?” Sherlock asks.

“I’m afraid not,” Wilder answers regretfully. “Have you tried the boy’s mother? He’s very fond of her. That seems the most likely place he’d have run away to. Or perhaps one of his school friends?”

The large frame, hazel eyes, and patrician chin are not the only traits that James Wilder shares with the Duke, and—not for the first time—Sherlock wonders if the ability to lie convincingly (or fail to, in this case) is genetic.

“Perhaps,” Sherlock answers noncommittally before standing.

“You’re not going so soon?”

“I’m afraid I must be off,” Sherlock says smoothly, smiling fixedly down at the other man. A whisper of nervousness begins to bloom in Wilder’s eyes. “I’ll stop by later, if I have any other questions.”

He passes the Duke—who is indeed holding a glass of water, though he seems uncertain of why exactly he has it—on his way to the door.

“Mr Holmes?”

“I’ll tell Mycroft you send your regards,” Sherlock says as he leaves. He wishes for a moment that he had a hat or cane on his person: some prop to twirl in his hand and mark a jaunty departure.

Kidnapping, indeed. Mycroft owes him: for forcing Sherlock to interact with the daftest of criminals if nothing else.

**

“This brings back memories,” John says, kicking at a stray stone on the path outlining the school’s perimeter. Sherlock had requested that John join him at the school immediately after leaving the surgery, and the chemicals that cling to his partner waft lightly on the autumn breeze as they circumnavigate the outermost buildings.

They have been exploring for almost an hour: John rambling about the irritation of an overabundance of welders underfoot in the surgery (apparently the renovations involve the introduction of high-quality steel beams to reinforce the walls, or some other such nonsense) and Sherlock recounting his visit to the Duke’s house. John had been particularly amused by Sherlock’s pantomime of the Duke’s nervous tics.

Sherlock stares at his friend in mock perplexity at the statement. “Of circumventing a structure while combing the ground for traces left by a likely non-kidnapped child?”

“No, of being in school. Berk,” John says, smiling. “It’s hard to believe we were ever that young, isn’t it?” He motions toward the cricket pitch where—rather than following traditional rules—a group of young men appear to be chasing one another around with the bats. Their shouts and whoops carry across the field.

“Mmm, I don’t believe I was ever that young,” Sherlock says, sparing a glance for the roughhousing boys before returning his attention to the edge of the pavement. “Is it too much to ask for the groundskeepers to be a bit less fanatical in their sweeping? What if the boy had actually been kidnapped?” he mutters.

John ignores him. “That’s a shame. I bet you were a handful.”

Sherlock keeps his eyes on the irritatingly well-tended ground. “Mycroft would agree with you, I’m sure. He took over my education after my twelfth tutor resigned.”

“Twelfth?” John asks, stifling a laugh. “What on Earth did you do?”

“At the time, I had a passion for reptiles: snakes, lizards, turtles. Those sorts of things. It was all very educational, not that any of the tutors my parents employed were perceptive enough to realize it. When Mycroft left for university, I created my own curriculum and educated myself.”

“That’s…not surprising at all, really.”

“Aha!” Sherlock stoops suddenly and peers at an imprint in the dirt just off the paved path they have been walking on.

“You’ve found something?”

“This is an imprint of a patched bicycle tyre. Given its depth and definition, it was ridden by a child weighing approximately 32 kilograms sometime within the last forty-eight hours.”

“Do you think it’s Saltire’s? Or the one he stole at any rate?” John asks. He has hunkered down next to Sherlock and, judging by his face, is enjoying the hunt as much as Sherlock had hoped he would. Given the situation (the perpetrator having been identified almost immediately), Sherlock wasn’t certain John would still want to accompany him.

“We can’t be certain, of course, but it’s plausible.” Sherlock snaps a photo of the tyre mark with his phone before looking off in the direction the bicycle had been travelling. East. Toward the school’s back gate, which—according to the file Mycroft gave him—is frequently left unattended.

“Why are we doing this, exactly? If you already think you know who did it-“

“I know I know who did it.”

“-then what’s the point of coming to the school at all? Shouldn’t you just tell the police where the boy is?” They are still crouched over the tyre mark, gently leaning against the other, which makes the moment rather more pleasant than the other occasions when Sherlock found himself hunkered down on the pavement.

“The Duke of Holdernesse never reported his son’s disappearance to the police,” Sherlock explains.

“But he called Mycroft?”

“Clearly he knew which source would be the more helpful.”

“I thought you said the father is involved,” John says, openly puzzled.

“He is now, but he wasn’t from the start. If he was, he wouldn’t have asked Mycroft for help. Presumably he’d know that Mycroft, above all others, would see through a false kidnapping scheme. If he was involved initially and merely trying to throw off suspicion, it would have been far safer for him to call the police.”

“But now he knows where his son is and is still pretending that he’s missing?”

“Yes,” Sherlock says resolutely, straightening up from his crouch. “Though if he’s at all clever—debatable from what I saw—he’ll report that the boy ran away to his mother’s house in France and was recovered after a brief absence.”

John stays crouched, face scrunched up as he concentrates. “You think that the personal assistant is the one who planned it all, that’s obvious. But why would the Duke go along with it? Why not report him? Or sack him at the very least?”

“James Wilder is the Duke’s son.”

John’s eyebrow rises. “That’s unexpected. You’re sure?”

“Their bone structure is strikingly compatible.”

“So Wilder, what?, kidnapped Saltire and then had a change of heart and confessed it to the Duke after he’d already raised the alarm?”

“Or the Duke discovered his involvement on his own. Either way, he chose to protect Wilder rather than alert others to his crime.”

“But, if that’s all true, why is Saltire still ‘missing’?”

Sherlock is beginning to lose interest in the explanation. Motives are by far the least appealing aspect of an investigation. “I expect Wilder hired a proxy to do the actual kidnapping—someone with actual criminal experience—and got in over his head,” he replies disinterestedly.

John frowns. “Are they in danger?”

“Not for long. They’re in the process of fleeing the country.”

“They’re fleeing the country?” John’s eyes go wide.

“Most likely,” Sherlock replies, taken aback by his flatmate’s shock. “The house is almost entirely packed.”

“We need to tell someone.” Occasionally John can become (rather endearingly) worried about the welfare of individuals with which he has no association whatsoever. It’s one of Sherlock’s favourite, albeit puzzling, traits of his.

“Why? The boy is in no danger, and if the state of the house is any indication, the Duke and Wilder will be out of the country later this evening.”

“Whoever it is they’re afraid of could still come after them,” John says stubbornly.

Sherlock sighs. “Fine. I will inform Mycroft’s assistant of my findings. She’ll no doubt see to it that they’re monitored. Will that do?”

“It will,” John says, mouth twisted into a lopsided, affectionate smile as he looks up at Sherlock. “Though you still didn’t explain what exactly it is we’re doing here.”

“There’s still the matter of the missing German instructor,” Sherlock reminds him. “I also thought it would be…enjoyable to work through the specifics of the case with you here.”

John’s smile is blinding. “You just wanted an audience,” he teases fondly.

“A specific one,” Sherlock agrees, willing himself not to descend (further) into rank sentimentality.

“So, now what?” John asks, standing up at last and dusting off his knees. His eyes are bright, and his cheeks are lightly flushed from their walk around the grounds. Sherlock wants to kiss him.

So he does. Even after six weeks, the realization that these moments are something he can have whenever he chooses is still a heady, unexpected delight. The boys on the cricket pitch catcall at the sight, but neither he nor John take any notice.

Sherlock steps back at last and grabs John’s hand at the wrist, pulling him in his wake as he strides back toward the school.

“Now, we search Saltire’s and Heidegger’s rooms.”

“For?” John asks, gamely keeping pace with Sherlock’s longer legs as they rush toward the school.

“Anything of consequence.” Sherlock bends his head toward his friend with a smile. “Barring that, toads and snakes. It’s my understanding that Saltire is an enthusiastic herpetologist.”

John returns his grin. “If you find any, you’re not bringing them home with you.”

**

David Heidegger’s classroom proves to be disappointingly empty of helpful evidence. The man clearly leads a Spartan existence, owning only a small case of books (primarily German texts) and a battered trunk (military in style) holding extra, rather threadbare, clothing. The file Mycroft had given him states that the man’s flat was already searched the day he was reported missing, with nothing revealing found, and Sherlock decides to leave his own search of the premises until the following day. Saltire’s dormitory bedroom is, if possible, even less revealing, and after an hour of fruitless searching, they return to Baker Street to pass the remainder of their night.

They pass it in an activity to which Sherlock is fast becoming addicted.

John is ticklish behind his right knee, the knee of his ‘bad’ leg. And for all that it’s psychosomatic, Sherlock likes to think of himself (is learning that he likes to think of himself) as a polite lover. He holds the leg up gently—ensuring full extension of the joint without overextending even slightly on the off chance that it may cause John some pain—as he runs his index finger lightly and repeatedly over the soft skin beneath.

John squirms delightfully. Then he accidentally kicks Sherlock’s head, which is less delightful.

“Sorry,” John breathes, not looking sorry in the slightest. Sherlock scowls at him, though—given the shambles their activities have made of his hair—he anticipates it lacks its usual ferocity. At any rate, John smiles up at him fondly from where he lays across Sherlock’s bed.

“Come here,” John murmurs, pushing himself up onto his hands and using the new position to slide his hand behind Sherlock’s neck and pull him down. Sherlock is required to release John’s leg, but his new position—spread atop his friend, the two of them pressed together from forehead to somewhere down near their knees—is worth the loss.

“Come here,” John says again, pulling Sherlock in for a kiss (admittedly there’s not any degree of resistance on Sherlock’s part) while simultaneously transferring his grip on Sherlock’s neck to his hair. Sherlock had noted John seemed inordinately fond of it—though he’s trying not to analyse its implications for John’s character too much, at John’s request—and the majority of their encounters over the last six weeks have resulted in Sherlock’s hair looking, upon conclusion, entirely wrecked.

Sherlock’s thoughts cut off as John shifts his knees up to cradle Sherlock’s hips and begins to move. It’s neither sinuous nor particularly elegant, but it is slow and deliberate, and it brings John’s arousal into direct contact with Sherlock’s own with each catch and glide of his hips. Sherlock presses down on him—automatically, helplessly—and John groans, throwing his head back and speeding up his movements, and Sherlock has no option but to reciprocate.

There’s little finesse in their coupling: John stated directly early-on that he has no patience for such things, and Sherlock had assumed, given his own character, that he would find them equally intolerable. But the touch of skin on skin and heat on heat is enough—more than enough—to bring them to an almost painful degree of arousal seemingly in an instant.

John groans once more as their joined hips begin to move more quickly before closing his eyes and falling silent beyond a few ragged breaths from a mouth he doesn’t close (a lovely, full mouth, Sherlock thinks, before forcibly cutting off the internal ode).

Perhaps unsurprisingly, Sherlock has discovered himself to be a silent lover, the vast majority of his attention devoted to watching John’s face and body for the most minute of reactions (‘creepy’ John had said; ‘thorough’ Sherlock had retorted). Until at last pleasure overwhelms him and he shakes apart, gasping, in John’s arms.

John follows a moment later and takes a minute to run a soothing hand up and down Sherlock’s back (as though gentling a nervous pet, Sherlock occasionally thinks uncharitably before dismissing the thought).

They lay there together, the heat between them cooling as the excess energy—energy they created purely by their mutual presence in each other’s orbit—is siphoned off into the atmosphere.

As after every sexual encounter during the previous six weeks, Sherlock reflects (marvels, really) at how absolutely perfect their rapport with one another is.

He also wonders, with something that is beginning to border on despair, why it isn’t enough.

**
Day 2:

It was clear to Sherlock within his first twenty-four hours of knowing the man that John Watson is a special sort: a man who stands out from the rest of the frequently dull morass of humanity through an air of quiet confidence and obstacles overcome.

(John also distinguishes himself due to his proficiency with firearms, as Sherlock learned in the second twenty-four hours of acquaintance.)

Sherlock additionally knows himself to be without peer; John can roll his eyes all he like at the evidence of arrogance, but he would never dispute the finding itself.

With two such competent, unmatched individuals merging their lives and energies together, Sherlock knows objectively that the resultant reaction should be explosive. Apocalyptic.

And it is. The problem—if it can even be termed as such—is that Sherlock has the slightest niggling (and sometimes not so niggling) doubt that he and John are doing all that lovers are supposed to do.

Physically their interactions are wonderful, but, though Sherlock has little practical experience on which to base the notion, he knows that there is more they could be doing together.

John has yet to come to Sherlock’s bed, instead choosing to direct all of their encounters to his own room or, more frequently, initiating them in shared spaces, primarily the couch.

And neither of them has attempted to initiate something more intimate than frottage and mutual masturbation (aside from one ill-advised attempt at oral sex when Sherlock had been feeling especially curious about the taste of another man; John had jerked in spasmodic surprise; his knee had impacted Sherlock’s chin hard enough to result in a bitten tongue, and that had been the end of that).

Not that any sexual act could be classified as anything other than intimate. But Sherlock knows that there are certainly more they could engage in. Or at the very least attempt to engage in.

He fears that John is holding back. And if John is in fact keeping a part of himself segregated and reserved, he fears the cause: Sherlock’s temperament, those obsessions that so frequently overwhelmed him…his past.

Sherlock knows he’s not by any means an easy person to have a relationship with. On some level, he doubts he’s even capable of maintaining one at all, recent evidence notwithstanding. But the idea that John might think so as well—might be waiting for the other shoe to drop and their new, precious connection to spectacularly combust—causes something in his chest to quail.

Sherlock doesn’t want to broach the topic because he knows John may misinterpret his motivation, and he certainly doesn’t want the other man to feel pressured to take their sexual interactions further than he is comfortable with.

But what if John is never comfortable? Or, worse still, what if he is never comfortable with Sherlock?

“Hey.”

The hail is followed by a blunt, lightly callused finger poking at Sherlock’s side. Repeatedly. He bats it aside before John realizes he has a ticklish spot of his own, though given Sherlock’s unmitigated reaction approximately a week previously, it is likely John already suspects this weakness.

The finger returns again, this time just to the left of his stomach (John has demonstrated an unexpected fascination with trailing his touch along Sherlock’s ribs). “What are you thinking about?”

“What makes you think I’m thinking about anything?” Sherlock feels John shift where he lies next to him on the bed. It’s late—or perhaps extremely early; Sherlock hasn’t bothered to check the time since his unquiet thoughts woke him—and the world outside is dark and hushed.

“You’re always thinking. It’s an unavoidable quirk of yours.” John is smiling gently, Sherlock can see in the dim light filtering into the bedroom from the lamp outside. The burnished gold of his hair is muted to grey in the dark, but Sherlock can picture it as clearly as if the room was flooded with light.

“Perhaps I was overcome by our activities.”

His friend snorts. “Maybe for twenty seconds or so.”

“You don’t credit yourself with much prowess as a lover.”

John pauses. “I’m not going to touch that one. But, no, you have that wrinkle you get when you’re pondering something complicated.”

“Wrinkle?” Sherlock’s hand rises automatically to his face, and John chuckles before lightly touching an area between Sherlock’s eyes.

“Until meeting you, I always thought you brilliant, academic types were above vanity.”

“It’s not vanity,” Sherlock corrects, closing his eyes at the enjoyable feeling of John’s finger as it continues its survey of his facial bone structure. “It’s practical. One can pass for older with an application of makeup and other stagecraft. It’s more difficult to pass for younger when the signs of age become apparent.”

“Mmhmm.” John’s tone is openly sceptical and warm with good humour. “I suppose those tailored shirts you favour are also practical, then?”

“Of course,” Sherlock says, reopening his eyes to meet John’s gaze in the faint light. As always, it threatens to steal his breath for just a moment before he catches himself. He hopes he moves past the ridiculous urge at some point before his reputation suffers too much damage. “What would be the point of clothing that doesn’t fit properly?”

“Most people get by just fine with what they buy off the peg.”

“Most people purchase piles of ill-fitting clothing on a whim only to throw it in the bin a month later. I order only what I need, when I need it. Practically.”

“So you only purchase practical silk then?”

“Now you’re being purposefully obtuse.”

John laughs and leans in to kiss him for an instant that quickly grows into a minute. Sherlock enthusiastically supports the lengthening of time.

John eventually pulls away, loosing a regretful sigh as he does so. “I need to leave for the surgery.”

“You were just there yesterday.”

“Yes, that’s the funny thing about standard work hours: they have a way of repeating in incremental blocks.”

“Call in sick,” Sherlock issues the order to John’s lips after closing the ground on his friend’s retreat. “God knows you’re likely to have caught something working in that place.”

“I can’t leave them short. They’re overworked as it is, and we’ll be closed the rest of the week while they knock down the walls to put in those damn steel beams, so today is the last opportunity to get patients in.” John refuses to be swayed by the placement of Sherlock’s hands on his shoulders, so Sherlock shifts them to more persuasive territory.

John gasps. “Sherlock,” he murmurs. As every time Sherlock hears that little quaver in his flatmate’s voice, a small thrill trembles up his spine.

“John,” Sherlock returns, tightening his grip meaningfully and beginning to lie slowly back down, pulling John with him.

John lets out a shuddering breath before abruptly pushing forward (suddenly lacking resistance, Sherlock falls flat on his back) and tickling Sherlock’s side. Sherlock lets go of his flatmate in surprise, and John darts in for a quick kiss.

“Later.” John’s voice is ragged, which is something of a victory. Sherlock supposes. “I promise.”

Feeling the heat that had been so promisingly kindled disperse, Sherlock waves a dismissive hand in John’s direction as he rolls over pointedly in the rumpled sheets. “Oh, go give injections or whatever it is you do there.”

John drops one more kiss on the back of Sherlock’s head before walking resolutely to the door: a ridiculous, if almost poignantly tender gesture. “I’ll be off at five so we can head back to the school. Have the kettle on, if you’d be so kind.”

John closes the door before the pillow Sherlock launches can hit him.

**

Sherlock is in the kitchen continuing his previously interrupted experiment—Gladstone sitting under the table watching intently for a dropped bit of food—when Lestrade rings. As such, it takes Sherlock five repetitions of his mobile alert (well above his average response rate) to answer, and even then, he is distracted by the phosphoric acid.

“Holmes,” Sherlock grunts, before immediately dropping the mobile to adjust the flame of the burner. Lestrade’s voice, tinny and entirely unintelligible, wafts from the floor.

“A moment, Lestrade,” Sherlock calls down to it. “My hands are full of ester.”

“Sherlock!” His name is recognizable as the Inspector’s voice rises in volume, and the dog cocks his head at the mobile curiously.

The liquid begins to boil over, and Sherlock grabs for it before it can land on the floor and eat through the rug. Again.

“Damnit, Sherlock!” Lestrade shouts into the line. “This is important!”

In Sherlock’s haste to remove the beaker from the heat, he grabs it clumsily and burns the side of his index finger. He translates the sudden pain into a loud stomp of his foot on the floor, and the phone flips from the force of the resultant vibrations.

Sherlock!” Lestrade calls again through the now upside down mobile.

“Sherlock?” Mrs Hudson, one floor down. “Is everything alright? Have you broken something again?”

He snatches the mobile from the rug with violent energy. “Everything’s fine, Mrs Hudson!” he shouts at the floor before stepping to the sink and sticking his finger under a stream of cold water. Seeing his new proximity to the cupboard, Gladstone whines at him hopefully. Idiotic animal.

“What?” Sherlock snaps—at last—into the phone. “If you’re calling to request my assistance on a case that will once again prove to have an entirely trivial explanation, I will have no choice but to send a series of embarrassing emails from your personal account.” The pain from the burn on his finger makes his voice especially caustic.

It takes him a beat to realize that the Inspector has not responded.

“Lestrade? If you’re going to disturb me in the middle of a delicate experiment, the least you can do is be present on the line.” His finger is beginning to show signs of a blister, which will severely hamper his violin practice. Bugger.

“Sherlock, you need to come down to the station.” Lestrade’s voice isn’t tentative, but the initial pause is more than enough to put Sherlock on guard.

“What’s happened? Is it John?” He asks immediately, calculating the worst possible scenario and moving forward from there.

The Inspector is quick to reassure. “No, no. John is fine. He’s at the surgery, right? Can you call him?”

“Lestrade, get to the point.” Sherlock cuts in impatiently. “What is it?”

This time there’s no pause. “Twenty minutes ago, Jim Moriarty walked into the Met and turned himself in.”

Then, after a minute of complete silence: “Sherlock? Are you alright?”

He feels a burning in his chest and consciously tells himself to breathe. His voice is unperturbed and assured when he responds to Lestrade’s tacit question.

“I’ll be there in fifteen minutes.”