Author's Note: I imagine this story taking place shortly after "The Hounds of Baskerville," but please don't expect it to fit in exactly with anything after that. Sherlock may well seem a little different at first here, but there's a reason for that, as you'll see if you keep reading.

Be warned: Some readers might find the age of the victim and what happens to him disturbing. There's no sex, torture, or gore, though. In the interests of realism, some of the characters do use strong language. It's nothing any child doesn't hear every day on the playground, though, sadly.

I'm grateful to Fang's Fawn for her willingness to chat at length with a new fan of the show, and for her very helpful encouragement, thoughts and suggestions for this story. I'm also grateful, as always, to Liz, for patiently answering my questions about British schools, and going above and beyond to get the information I needed. And I owe additional, and belated, thanks to sevenpercent for so graciously pointing out the mistakes I had made with blooming times, and offering alternatives.

Any errors that remain are entirely my own fault, of course.

All the usual disclaimers apply.

Basic Training

For all his years on the force, Greg Lestrade still finds the scene in front of him unsettling. He's not the only one: he can tell Sally Donovan is bothered by it, too, though that might not be as noticeable to anyone who doesn't know her as well as he does. Even Phil Anderson seems shaken, while the young constable from the local station is still green around the gills.

And yet there's surprisingly little blood, and none of the horrors the Met's top homicide team encounters all too often. No mutilations. No evisceration. No burns. No indications of torture. Just a very young boy lying on his back in a flowerbed full of daffodils - eyes open, soft lips parted a little, and a long, slim-bladed sword protruding from his chest.

"Bloody hell," Sally mutters, wiping her mouth with the back of her hand, a gesture Greg recognizes as a sign of emotion. "What is he, eight? nine?"

"Ten." Jonathan Gillespie, the school's headmaster, shakes his head sadly. "That's the earliest we admit them. Awful business, this. Terrible. His parents are - well, you can imagine."

"They're here?"

"In my sitting room. I left my deputy head with them - and our Matron, of course. Thank you for coming so promptly, Detective Inspector. I really do appreciate it."

Greg nods in response. His hands are in his pockets, his eyes fixed on the scene in front of him, working to take in every scrap of detail they can. Gillespie clears his throat.

"Er - Might I ask - was Mr. Holmes willing to come as well?"

Greg looks up then.

"Yes, he should be here shortly," he answers. "Along with his colleague, Dr. Watson."

The relief that floods Gillespie's face would be irritating, if Greg weren't so used to the response. Sally makes an impatient noise; Anderson rolls his eyes. The headmaster - well-used to catching those looks on schoolboys' faces, but not at all accustomed to them from adults - flushes a little.

"My apologies," he says. "I don't mean to suggest, of course, that your force's work might be in any way insufficient. But the parents - all the boys' parents - will want to hear that, well, that every possible step is being taken to resolve this matter quickly, to apprehend the person who has done this terrible thing. The more minds at work, the better, surely."

"Of course, Mr. Gillespie. We understand." Greg hears Sally's annoyed huff behind him, but ignores it.

"Then I'll leave you to it, shall I? I should be getting back to those poor people."

Greg nods absently, his eyes scanning the ground again. The headmaster leaves, walking back along one of the flagged paths towards the school's main cluster of buildings. As he passes under an alley of flowering trees, a robin flutters in the branches overhead, sending a shower of waxy magnolia petals raining down around him. He doesn't appear to notice, but continues on, shoulders a little stooped, hands clasped in a melancholy posture behind his back. Above him the sky is grey and heavy-looking. "Rain," Greg thinks, and "Could start any time."

"Get going, then," he tells Sally and Phil, and they get to work, setting up a protective canopy, photographing the scene, dusting for prints. The boy is wearing his school uniform: grey trousers, blue shirt, blue blazer with the school crest on the upper left pocket. They turn out all his pockets, producing the boy's mobile (a year-old iPhone, still in good condition, in a dark purple case), a couple of pencil stubs, a broken eraser, several empty Tic-Tac boxes, a pair of rather grubby-looking tweezers, a length of knotted string, a small plastic object that on closer examination proves to be a folding pocket loupe, a handful of coins totalling £4.63, an Oyster card, and - to Greg's surprise - a paperback copy of Othello.

"Tough reading for a sixth-year," Phil says, when Sally fishes this out.

"It's a good school," Greg sighs. His own kids are at an ordinary, state-run primary, where Shakespeare plays no part in their curriculum yet. He wonders if he really has done them a disservice by not being able to pay for this kind of education for them. Their mother certainly thinks so, but then, she finds pretty much everything he has done or is doing wrong these days, anyway.

He flips through the book. The boy's name is written neatly inside the front cover - Gareth Sheldon-Jones - and the margins are full of doodles, mostly geometric shapes and numbers. The boy clearly hadn't found the play very interesting.

Greg isn't surprised; he can't imagine any child being able to make his way through Othello at that age. The teacher must be bonkers, assigning something like that to ten- and eleven-year-olds. Or maybe it was the school that demanded it. Trying to score points with the parents, probably: "Send your son here, and he'll be reading Shakespeare in Year Six!" As if it would mean anything to a boy that age, even if he could slog his way through the language, which the state of the book indicates that this one couldn't. Greg will have to point that out to his ex, the next time she gets onto him about the kids' schools.

"Looks like he was killed right here, sir," Sally says. "You can see the footprints - his, here, and these others, there. From the way they overlap, it looks like there was a scuffle. The palms of the boy's hands are a bit cut up; he must have been trying to defend himself. The prints are a man's size nine smooth-soled brogues. We're looking for a bloke between five eight and five ten, I'd say. Or - " she hates the thought, but there's no way around it - "an older boy."

Greg nods. He's come to the same conclusion. He hopes to God it isn't a boy, but at a school full of adolescents there's no getting away from the possibility - probability, even - that the five-foot-eight-to-ten killer is under eighteen. Best hope, it was an accident. Actually, that's the most likely scenario he can think of: two boys fooling around with swords, the worst happens, and the other boy flees in terror, taking the second weapon with him.

Where did they get the swords, though? Well, that isn't hard to figure - the school probably has a fencing team; this sort of place always does. He can have their equipment lockers checked to see what's missing. Though the weapon in front of him doesn't look as if it's been accustomed to regular use. In fact, looking at it more closely, he wonders if it's really a fencing foil at all. It looks quite old. He'll have to ask if there's a display of antique weapons in the school buildings anywhere. It wouldn't surprise him to find there's a whole collection of them hanging on a wall in some Great Hall up there - ridiculous, if they aren't secured somehow, but again, the school seems like that kind of place.

Greg knows he can't afford to rule out other, more sinister, possibilities, though. Children do sometimes kill each other on purpose, even children as cossetted and wanting for nothing as boys at a place like this. Or the killer could be an adult: a teacher, a member of the grounds staff - there are plenty of options. This corner of the gardens is a lonely spot: the boy might have seen something he shouldn't, something the perp would have thought worth killing to keep quiet. Drug exchange? Sex? If he'd come across a couple of married teachers having sex - no, surely no one would kill to keep that quiet these days. Not unless there was money involved. Well, what if the betrayed spouse was wealthy? Or powerful? If a teacher was having an affair with, say, the head's wife, or with the wife of a member of the board of directors - if his job depended on the affair not being found out . . .?

Or Gareth might have caught a teacher having sex with another student. That might seem worth murdering over, Greg thought. If it came out, the result would be total professional annihilation, social ostracism, and very likely imprisonment.

Of course, the sex might not have been with another student. . . .

"See any signs of sexual assault?"

Greg knows the answer already, but he likes to take his team through their paces when he gets a chance. He's responsible for their training and advancement, as well as for solving the crime. This kind of question is basic, but there's never any harm in reviewing basic training once in a while.

The other two shake their heads.

"Not that I can see, sir," Sally says. "His clothing seems intact - belt and zip still done up, shirt tucked in, tie neatly knotted, nothing torn or out of place."

Greg nods again, oddly relieved to have his own observations confirmed. What happened to this child is bad enough, without having to think of him going through that.

At least, not here, not just before he died. Something could have happened earlier, though. The child could have met his abuser here - by accident? appointment? - and threatened to expose him, then been killed to keep him quiet.

There are times when Greg really hates the way his profession has taught him to think. But it's a job that has to be done, and he knows he's good at it, even if he has no hope of ever being as brilliant as -

As if the school was that even better-known one, and Greg had muttered "Accio!" instead of just thinking of a name, another fluttering of wings and petals announces two new arrivals.

"Oh, wonderful," Phil sighs, nudging Sally and rolling his eyes again. "Freak's here."

000000

Sherlock lopes down the flagged path in a swirl of coattails, his face half-hidden by his collar, John Watson striding along half a step behind him. Sally allows herself a moment to wonder, as she often does, just what the hell attracts the smaller man to his companion and to this sort of work.

He doesn't seem the type. He's a doctor, for crying out loud, and doctors are supposed to fix people, not rip them apart, physically or psychologically, like the Freak always does. The Freak talks too fast, is always barging in where he doesn't have any business going, and is incredibly rude; John, on the other hand, always seems quiet, professional, polite. The Freak stalks around in that ridiculous coat that makes Sally think of Dracula, or maybe Snape; John wears those dumpy-looking jumpers and brings words like "ordinary," "beige," and "mild-mannered" to mind.

(If Sally were really giving these thoughts her full attention, that last phrase might ring a warning bell - but she isn't, and it doesn't. John isn't the kind of man she gives her full attention to. She'd never notice him in a crowd if he wasn't joined at the hip to the Freak.)

Phil thinks they're a couple, an idea that makes Sally laugh - she just can't imagine the Freak having sex with anyone, or anyone wanting to have it with him, even though he really would be quite good-looking if he weren't such a colossal berk. Lestrade, who knows both of them a lot better than either Phil or Sally does, insists they're just, "Flatmates, Anderson. Colleagues. Friends." Sally doesn't know which she has a harder time believing, Phil's version or the D.I.'s. It's not that she doesn't know other people who economize on the rent by sharing flats, and spend a lot of time together without being romantically involved. But the Freak doesn't have friends. She can't picture him ever having had one at all, before John Watson came along.

(If he were almost anyone else, that might make her feel sorry for him, but "sorry for" and "the Freak" are two concepts that just don't work together in Sally's mind at all. They're like a base and acid, or - Sally's got a younger brother who's keen on science - matter and anti-matter; if you even tried to put them together, the earth would quake, volcanoes erupt, and the whole world just self-destruct.)

It's not that Sally really cares what John Watson and Sherlock Holmes are or aren't to each other back in Baker Street. What she cares about is that they're here, now, and they're about to interfere with a crime scene she's working on again. It's what they always do, and it drives Sally nuts. She's had to work so hard - black girl from the estates, fighting to get through school; black woman, fighting to get ahead in a white man's job, a white man's world. The deck has been stacked against her from the start, but she has guts and grit, and, yes, in spite of what he always says, talent and intelligence, and she's fought her way up to Detective Sergeant on the Met's top homicide team. She's proud of that, damn it. She has every right to be.

So it galls the hell out of her that Sherlock bloody Holmes, with his public-school voice and designer clothes, with his complete contempt for proper police training or hierarchy or procedure, and with, most of all, his absolute and total lack of any need to have ever worked or fought for a single thing in his whole sodding, over-privileged life - it just totally pisses her off that this pampered, poncy mummy's boy is able to sail right in over her head and solve a case before she's even had half a chance to think about it, for Christ's sake.

It's bothering her more than usual today, because today it wasn't even the D.I. who decided to call the Freak in. He almost never does that at the beginning of a case; he only asks Sherlock for help when he's really up against it and the team isn't producing the answers he needs at the rate he needs them to. Sally hates it when Lestrade does that, but at the end of the day he's her D.I., she respects the hell out of him, and she's proud to be his sergeant and a member of his team. So she can just - just - make herself put up with the Freak's presence on other occasions, even though she can't make herself pretend to like it. Or him.

But today is different, because it wasn't Lestrade who'd decided Sherlock ought to be there at all. It was the school's board of directors who'd asked to have him called in. And whatever that headmaster might have just said, it's as plain as the nose on Phil's face that they're putting their trust in the Freak, not in the Met or her team. The injustice of it makes her smoulder.

That's not the only thing getting to Sally, though, as she watches the long black coat flapping just above the petal-strewn path. She may be as tough as nails on the outside, but under all that attitude she has a heart, and the sight of that little boy lying dead among the daffodils has wrenched it badly. He looks so young - much too young to die at all, let alone in such a horrible way. Whoever did it must have really hated him, she thinks, and He must have been so scared.

She tries to remind herself that kids die every day, most of them - kids in Africa, kids in Chicago, kids right here in London on estates like the one where she grew up - after much less cossetted lives than this boy would have had. It doesn't help much. He's still just a kid. She hates looking at his small body. She hates what happened to him.

She hates what's happening to his parents, too. Those poor, poor people, she thinks, and wishes there were something she could do to help them. But there isn't, except to find the psycho who did this to their son as fast as possible.

A part of her knows that if that's what she wants to do, she should be glad Sherlock's here. There's no question that he's good at this, amazingly good. But as she watches him approaching, all she feels is anger and disgust. The very last thing those people need, she thinks, is to have to see the Freak dancing around their son's body, showing off the perverse pleasure he always takes in murder - or to hear the callous, awful, horrible things he's absolutely bound to say to them.

Bile washes up in Sally's throat at the thought of it, and she has to turn on her heel and put in three brisk laps around the walled garden before she's calm enough to rejoin the team and watch the Freak do his thing over that dead child.

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Sherlock stands for a moment and surveys the scene. They're in a walled garden, one of a series of stepped gardens terraced down the side of the hill the school is built on. This one is a long rectangle of beautifully manicured lawn, surrounded on all four sides by perennial borders and high brick walls. There's an arched wooden doorway at each end: the one he and John have just come through, and one opposite it.

The body is lying under a police canopy in a perennial border that runs along one of the walls. It's a very old wall - probably Tudor - and is due for repointing sometime soon; the mortar between the bricks is starting to crumble, and small plants have begun to move into the cracks. Great swaths of wisteria and ivy hang over it, their suckers undoubtedly contributing to its decay. A clematis is in full, effulgent bloom.

It's April, so the bed is planted out in daffodils, and overhung by the pink and white blossoms of the magnolia trees in the upper garden. Both daffodils and magnolias are a little past their prime. Petals are dropping from the trees; a few lie scattered across the boy's body, clearly deposited there before Lestrade's team erected their canopy over it. Patches of the daffodils have been flattened down in places - the footprints that Sally and Phil have already noticed.

Sherlock seems more interested at first in the garden wall than he is in the body or the prints. Eventually, though, he bends down to look at the indentations in the daffodils. After a minute he rises, steps over them, and squats down next to the boy. After another minute, he holds out a hand, palm-up.

It takes Greg a minute to realize what he wants. Sherlock doesn't snap at him for the delay, but continues to study the boy silently, hand outstretched. There's something absent-minded about the gesture, as if he's hardly aware he's making it. Greg finally figures out what he wants, pulls out a pair of gloves, and hands them to him; Phil and Sally watch with shock as Sherlock draws them on. John feels a jolt of surprise too. He narrows his eyes a little, watching his friend with more than his usual care: something's different, he thinks, but why?

Sherlock finally draws his eyes away from the boy's face. He looks at the sword's hilt carefully, glances at the cuts on the boy's hands, checks his pockets, then dives into the evidence bags that Greg simply hands him without being asked. The whole scene takes place in a silence that everyone watching finds disconcerting.

Sherlock opens the evidence bags and turns out the contents. He unfolds the loupe and examines it; peers into the Tic Tac boxes, shakes them, and sniffs them several times. He does the same thing to the tweezers. The string seems to interest him, too; he looks it over intently, an odd expression flickering over his face as he runs his gloved fingers along it. Finally he opens the book and flips through the pages, looking at the doodles with apparent interest before pausing on one of the last pages where - to Greg's chagrin, as he hadn't noticed this before - the text has been underlined in purple pencil.

It seems to be Othello's last speech. The teacher must have told them to pay attention to that one, Greg thinks; it would be on the exam for sure.

Sherlock's face hardens. He shuts the book, glances over at John, and tips his head at the body wordlessly. John looks at Greg for permission, gets a nod, and kneels down beside the child. Sherlock leaps up and whirls away to stalk around the garden, looking, Sally thinks, like a big carrion-eating crow. Like a crow, too, from time to time he pecks suddenly at something on the ground. Greg suppresses a sigh. None of the places Sherlock is poking at are ones where his team has noticed anything at all.

Eventually the detective stalks back to them again.

"John?" he says. There's a harsh note in his voice that strikes Greg as somehow different from the usual irritation, annoyance, or indifference he's used to hearing there. John notices it, too: Greg sees the way his brows pull together as he lifts his head, the intent look he gives his friend before answering.

"From everything I can see without an autopsy, it's what it looks like: a single thrust just below the heart. The blade has penetrated deeply - almost 12 cm, I'd say - and remained in place, so the bleeding was mostly internal. The hands are a bit cut up, of course, but those wounds are superficial and didn't contribute to the death."

"How long did it take?"

"It depends. There've been cases of adult men surviving stab wounds like this; I've read one case-study where the victim drove himself to the hospital afterwards, and lived. But that was a stiletto; this blade is wider than that. This wound, in a child this size - he was probably gone in a few minutes."

"Pre-pubescent?"

"Almost certainly."

Sherlock puts his hands in his pockets and swirls away across the gardens again. Greg watches him go. So does John.

"Something's off with him," Greg says. "None of the usual excitement over a new case. He didn't ask you when the death occurred, even though he wanted to know how long it took. And he didn't even look at the boy's phone."

"Couldn't work the screen through the gloves?"

"When has that ever stopped him?"

John nods slightly. He's still watching Sherlock as he strides around the garden. Something is off. There is, as Greg said, none of Sherlock's usual excitement at the beginning of a case. He's too quiet: isn't rattling out his deductions, isn't snapping with exasperation at Greg's team for having got to the scene first and messed with the evidence, isn't even responding to Anderson's and Sally's quite audible snide comments. He hasn't called them idiots once.

And yet it's not that he's subdued. John isn't sure it's possible for Sherlock to be subdued,and he certainly isn't now; he's all tension - only not quite the same kind of tension that John is used to thinking of as normal for him. The skin of his face seems to be pulled more tautly even than usual over his bones, and there's a - the only word John has for it is darkness - in his eyes, that John has only seen there on a few occasions, when the man has gone much too long without something to immerse his mind in and he's pacing the sitting room floor, making wild, dissonant sounds on his violin at three or four in the morning. Those are the times when John stays up and pretends to be drinking tea and reading some popular novel, because even though his bedroom is upstairs and he could block the worst of the noise with earplugs if he wanted to, he's worried about what Sherlock might go out and do if he isn't there to stop him. He's not sure if Sherlock is a recovering addict or just an occasional user who really can, as he claims, stop when he wants to, but he doesn't care to take any chances. One bad hit can kill you, either way.

"We should be getting on with the interviews," Greg says. John nods.

"We'll follow you," he says. "At least, we will if he wants to."

"'Try to get him up there if you can, please, John. The school's directors really want him on the case. They made it clear they'd go to him themselves if I wasn't willing to bring him in, and equally clear that my Assistant Commissioner is a close personal friend of the chairman of their board."

"I'll do my best."

"Thanks, mate. That's all a bloke can ask."

Greg leaves the local PC in charge of the body, and takes Donovan and Anderson with him as he goes back to the school to start the interviews. To John's surprise, Sherlock walks back across the lawn and follows the policemen through the gardens and up the hill to the main building, a Tudor pile of time-worn brick and stone. John keeps pace with him. Neither man says anything until they reach the school's massive front doors. Then John stops and clears his throat.

"Sherlock," he says, in warning tones. "Be nice."

The look the detective shoots him is hard for even John to read.

"To-?"

"The boys' parents."

Sherlock nods briefly. It isn't the response John was expecting.

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To listen to the school staff talk, Gareth Sheldon-Jones was their star pupil and the place will never be the same without him. Every teacher has some version of the same thing to say: "Very bright boy - very bright indeed. Brilliant future ahead of him, brilliant. Terrible thing to happen, terrible. A great loss to the school. A great loss . . ."

The accolades would be more impressive, Greg thinks, if they weren't quite so formulaic. They're what every report in every newspaper always says, whenever a school child dies.

Gareth's classmates are more reluctant to say anything at all, but just as polite when they do. "He was really good at running. Won lots of ribbons last field day." "Champion swimmer; swept the medals last term." "Really excellent fencer. Took gold at the nationals last month, and he was the youngest on the team."

Nobody has anything bad to say about him, but it's hard to get anything more out of them than this. They're decent kids, obviously, too shocked by the death of a classmate to be able to talk about him yet. Greg thinks how his own son would react if something like this happened to one of his mates, and feels guilty for having to put the boys through this at all.

The other questions he has to ask make Gareth's classmates even more uncomfortable, but as far as Greg can see, they all seem genuinely shocked by the idea that anyone - teacher, staff member, or another student - might have been using the boy sexually, with or without his consent.

"Not bloody likely!" most of them reply, heatedly. "No one here would do that!"

"Things do go on, you know," one of the older boys - Greg doesn't confine his questions to the sixth year - says, more candidly. "There are gay chaps here, of course, but they're all doing it with each other, not with the lower-school boys. Everyone knows what everyone else is up to, you know; it would be awfully hard to pull something like that off without half your form knowing. And the teachers are all fine; they don't mess with us. Besides, he was just a day kid, wasn't he?"

Like most of the lower-school boys, he was - one who always left school promptly when classes were over, getting home in time for tea. Which certainly makes it less likely, Greg thinks, that he was being victimized in that way; there aren't many opportunities in a school like this for a teacher or an older boy to be alone with a younger one, not in today's climate of caution. As for the parents themselves, while they'll have to be thoroughly investigated, all Greg's instincts are telling him that they're both good, decent people who had nothing to do with their son's death and are genuinely devastated by it.

Sherlock hovers at the edge of these interviews, playing with the boy's iPhone, which has been fingerprinted by now, and which Greg hands to him with a request that he figure out how to unlock it. John watches that exchange with amusement, admiring the D.I.'s deftness in finding a way to keep Sherlock busy and out of trouble while the interviews are conducted. John is determined to keep a sharp eye on his flatmate himself, ready to intervene if he launches into one of his rounds of tactless deductions or sarcastic put-downs of the teachers, the students, or - God forbid - the poor boy's parents. But Sherlock surprises him by listening quietly, seeming to concentrate most of his energies on the phone.

000000

When the long day of interviews is finally over and evening is drawing on, Sherlock says he'd like another look at the scene. Greg, rather sadly - he missed lunch, and is feeling quite peckish - declines the headmaster's offer of tea in his private rooms, and accompanies Sherlock and John back down to the garden. Sally and Phil follow. The light is fading; it's started to rain.

"Sounds a bit sickening, really, if you ask me," Phil says, loudly. "Little swot. Half the class probably wanted to do him in."

"Shut up, Phil," Sally hisses. "He was just a kid." She hasn't had anything to eat all day, either; the hunger isn't improving her self-control.

"No, really, Sal, think about it. All those top marks and awards and medals. He just took gold at the nationals in fencing, and he was only ten? We should be looking at the rest of the team."

They all gather under the canopy. Greg dismisses the forlorn constable, who heads gladly off home to his wife and tea. Sherlock walks over to the body and stands with his hands in his pockets, looking down at the boy. The others watch him curiously.

"There'll be another one," he says, after a long silence. His voice is somber. "And then another after that. And another after that."

Greg blinks. It's the last thing he's been expecting Sherlock to say.

"You think this is a serial killer, then? Why ever? There hasn't been another killing like this anywhere I can think of, not since I joined the force."

Sherlock doesn't answer. Baffled, Greg goes on: "If you think this bloke is going to strike again, we've got to stop him. We can't have a series of dead kids on our hands."

"There's nothing you can do to prevent it, Lestrade."

Sally scowls; Phil sneers. John watches Sherlock intently. If anyone were looking at him, they'd see the concern etching itself deeply into the lines of his face. But no one is looking at John.

Greg stares at Sherlock incredulously. "Why not?"

"There isn't any bloke, Lestrade. Haven't you realized that?"

"You think a woman did this?"

"He's just messing with you." Sally's voice is harsh, a file rubbing over sandpaper. "He's a freak."

Sherlock's face tightens.

"Try to use what brains you have, Sally," he says. "This wasn't a murder. Therefore, no murderer - no bloke, no woman. Is that quite plain enough for you?"

"Not a murder?" Greg stares down at the ground - the crushed daffodils, the two different sets of footprints, the long sword in the boy's chest. "Manslaughter, then? I did think of that. Two boys fooling around with swords, an accident, the other boy flees, taking the other weapon with him. But . . ."

"It wasn't an accident."

"What then?"

"Suicide, of course."

"Suicide!?"

Greg stares at him, bewildered. It's impossible. The boy was only ten years old. Even if he'd had a reason to do it - and Lestrade can't imagine what could possibly have driven a child that age to such a desperate act - why would he have done it like this? And how?

Lestrade remembers from his own school days that Roman generals had a habit of falling on their swords, but he can't see how this boy could have done that. The blade is longer than his arms, too long for him to have held it out point-first in front of him. Even if he'd somehow managed to anchor it in the ground and drop himself on it, he couldn't have gotten up enough momentum to get the blade embedded in himself so deeply. Could he have climbed the wall and fallen on it from there? Who would do that? It would be terrifically hard to get the aim right, and he'd have been found face down, or collapsed on his side. But he's lying on his back.

"The facts should be obvious, even to you, Lestrade," Sherlock says. "Those footprints could not have been made by two boys fencing with each other. Nor were they made at the same time. The dead boy came through that gate" - pointing at the door in the wall opposite the one they'd all come in at - "and along the path, there. You should be able to tell that quite clearly from those prints" - gesturing at two barely visible impressions in the mud that had gathered on a partially sunken flagstone some thirty meters from the body, near the other gate. "He would have come from the dining hall, where there is an impressive display of eighteenth-century duelling sabres at the back of the dais."

"How do you know that?" Sally asks, sharply. "You've only been in this garden and the reception rooms where we did the interviews, haven't you?" Sherlock ignores her.

"He chose a sword because he was a fencer, but he couldn't use a modern foil - they're too safe. So he took an old duelling sword from the dining hall. He chose this place because the wall behind the flower bed needs re-pointing; the gaps between the bricks would allow him to fix the pummel of the sword in one of them at chest height. You can see the scratches on the bricks here, and the corresponding ones along the pommel and grip."

Greg looks. Sherlock is right: there are tiny scratches on both the bricks and the handle of the sword. Greg hadn't noticed the ones on the pommel before, but even if he had, he would never have thought to look at the wall.

"He secured it by pushing in small pieces of broken brick. You can see them scattered on the bed just below it."

"Pretty convenient, bits of broken brick just happening to be lying around here, waiting for the kid to use them for some nutter scheme," Phil Anderson mutters, glowering.

"You are a waste of breath, Anderson. The boy took a brick from the edging along the flowerbed and smashed it on one of the flagstones to break off the chips. Didn't you notice the reddish marks and the bits of brick on the path here?"

Greg and John look. They're there, of course, all but invisible beneath the pink and white magnolia petals.

"He put the brick back." Sherlock leans down, and, after a moment's consideration, plucks one from the border; it comes up easily in his hand. When he brushes the soil away from its jagged edges they're obviously unweathered, fresh and sharp.

"He wedged the chips in around the pummel, walked back to the far side of the garden - did you really miss his footprint in that bed over there? - and ran at the sword, impaling himself on it. The force of the impact knocked the chips out of the gap - they're still here, in the flowers under it - and loosened the pommel, but didn't kill him right away. He brought up his hands and grasped the sword, either to try to pull it out of his chest, or, more likely, to thrust it in further. The blade cut his hands, and the pommel fell out of the wall. The boy collapsed on his right side, and lay there till he died. You can see the stains left by the daffodils on the right side of his blazer and shirt, and these pinkish marks on the other side were made by the pollen from the magnolia petals that fell on him after he died."

Everyone looks at the boy's shirt and blazer again. No one had noticed the faint marks on them before.

"Some time later, the owner of the size 9 shoes comes along the path from the opposite direction, sees the boy curled up in the flowerbed, and approaches him. He wouldn't have noticed the sword at first; it's thin, and the boy was lying with his back to the path, so his body would have partially concealed it. The newcomer turns the boy onto his back to find out what's the matter with him, and probably to try to help him, but the sight of a dead body with a sword through it unnerves the would-be good samaritan and he runs away, saying nothing to anybody about his discovery for fear of being accused of killing the boy."

"Yeah, right." Sally has been leaning against the wall a few feet farther along from the body, her arms folded across her chest. Now she uncurls herself and walks over to Sherlock, thrusting her chin up aggressively to stare into his face.

"So you've found some bits of broken brick and a few scratches on the hilt of that sword and on the wall. You've got no real proof that they have anything to do with each other, or anything to do with this kid getting stabbed. They could easily have happened some other way, and they probably did, because you haven't said a single effing thing about a motive. You want us to believe that a ten-year-old kid just decided to stab himself through the heart? Do you have any idea how rare it is for a kid that age to do something like that? No, of course you don't; what would you know about kids?"

John clears his throat. Nobody notices.

"A kid from a good, loving family - anyone can see those people up there aren't acting, they loved him. A kid who's getting top marks on all his reports, whose teachers have nothing but praise for how bright he is, who wins medals in three different sports, including the national fencing championship, where he was the youngest boy there and took gold? That's the stuff effing school heroes are made of, Freak. And he was only ten! Still pre-pubescent, the doctor here tells us," - she glances at John, her voice flickering with disdain - "and his house matron and the head nurse at the infirmary agree. So he wouldn't have been having any kind of sexual identity issue yet, and all our questioning has turned up no hint of sexual harassment from teachers or other boys, or anything to suggest it was happening outside of school. We're talking about a brilliant kid with a great family and the whole effing world ahead of him. And he decides to go and off himself? Choosing a really difficult and nasty way to do it?"

"Yes," Sherlock says, flatly.

John, who has been looking sorrowfully down at the dead child while Sally was speaking, raises his eyes to his flatmate's face again and tenses.

"So he was, what? Off his nut?" Sally demands. "Stark, raving, barking mad? And nobody noticed?"

Sherlock shrugs.

"That's absolute bollocks. You believe that, Freak? You don't know a single sodding thing about real people, do you? How could you? You come trotting round to crime scenes like this because you love looking at dead bodies, you get off on it - "

"Donovan," Greg says, in warning tones, but she's too worked up to really hear him properly, let alone to stop.

" - you don't give a shit about anything or anyone except your freaking self and your freak thrills. You have no idea how real human beings feel; you never will - "

"Donovan!"

"'Cause you're just a fucking freak, and if Lestrade listens to your crap, if he tells that poor couple up there that their son killed himself, just because you said so, because that's what gets you going, I'll - I'll - "

"Donovan! Shut it. NOW!" Greg roars, and she does hear that. Her mouth snaps shut and she stares back at him blankly. Then she drops her eyes to the ground and hugs her arms around her. She's surprised to find she's shaking.

Greg gives her a look that says, "I'll talk to you later, and you won't enjoy it," and turns back to Sherlock.

"If this was a suicide, why did you say we wouldn't be able to stop the next one? Teen suicides often lead to copycats, but in this age group? It's got to be a one-off, surely."

"Only you would think so."

Greg runs a hand through his hair, and sighs. Sherlock is amazing at this work, brilliant, and Greg has long ago enured himself to the insults, but he still wishes the man didn't always make him feel like such a tit.

"Sally's right, Sherlock. It's hard to imagine even one like this, let alone a string of them. I've been on the force over twenty years, I've seen a lot of suicides, and I've never seen one like this before. Teenagers, yes - too many. But not a kid this young, or with this much going for him."

"You weren't looking very carefully, then. Not a surprise."

Sally glares at him. John clears his throat again.

"They don't understand, Sherlock."

"Damn right," Sally mutters. "Who could understand a freak like him?"

Then she sees the way the doctor's usually mild expression is hardening as he looks at her, and feels the heat rising unaccountably in her face.

"I'm five hundred miles behind you, as usual," Greg says, wearily. "Take pity on a poor sod and just tell me what the hell you're talking about, would you? What on earth could make any child want to do this, for God's sake?"

"What could make him? You've been talking to this boy's parents, his teachers, his schoolmates all day, but you haven't heard a thing they were really saying, have you, Lestrade? One teacher after another says "star pupil" and you think, 'Very good student. Top marks. Great future' - as if that's what they're talking about. You didn't even ask what they meant by it. But you shouldn't have had to ask; you shouldn't have had to look any further than the boy's pockets."

Greg raises his eyebrows.

"Empty Tic-Tac boxes? String?"

"Yes, empty Tic-Tac boxes and string! Did you really think he just liked mints? He'd been using the boxes to collect samples of different kinds of soil - from the gardens around here, from his route home - and droppings and scat from at least ten different kinds of birds and animals."

"Oh, gross." Sally's face wrinkles in disgust, while Phil laughs, and says, "Dirty little bugger. I told you he was sickening, Sal."

"No," John puts in, quietly. "It's what any budding scientist, or even some future med students, might do. He used the tweezers to pick the samples up, didn't he?" Sherlock nods. "He probably analysed them in the school lab to see what they were composed of - what the animals had been eating, that kind of thing."

"Hence the pocket loupe," Greg realizes. "What about the string?"

"He was experimenting with different knots," Sherlock says. "Some of them are quite complex. He probably enjoyed the challenge of working them onto a single string; it wouldn't have been easy."

"There's more to them than that, isn't there?" John asks, sounding surprised.

"Ah, I thought you might have noticed," Sherlock answers, and for the first time that day he sounds almost pleased.

"Noticed what?" Greg demands, trying to tamp down his frustration at John having observed something, other than medical evidence, that he hasn't. "Let me see that again, Anderson."

Phil hands him the evidence bag. Greg takes the string out - everything's been photographed and dusted for prints by now - and looks at it carefully, trying to see what he's missed.

"It's Morse code," John explains. "The large knots are dashes; small ones, dots."

"Oh." And then, "I didn't think they used Morse in the army anymore."

"They don't. I learnt it as a kid."

John tries to take the edge off his accomplishment with a self-deprecating shrug. Greg feels annoyed with himself: he'd learnt Morse as a kid too, in Scouts, but he'd forgotten most of it by now, and hadn't recognized it.

"Does it say anything?"

John's eyes flick sideways to Sherlock's. There's a split-second hesitation, then Greg sees Sherlock tip his head a fraction of an inch in John's direction, as if giving his friend permission to do the interpreting.

"That's an 'i,'" John says, pointing to the first two knots on the string. "The next set's an 'n'. Then a, l, e, p, p again, o. Then o again, n again, c, and e."

Greg thinks about that for a moment.

"In Aleppo once."

"Yes."

"That sounds familiar."

"Yes."

"Isn't it-"

"From Othello's last speech. Yes."

Greg puts out his hand again; Anderson gives him the book that was in the boy's pocket. He finds the passage underlined in purple on the last page of the text, and reads it out loud:

And say besides, that in Aleppo once,

Where a malignant and a turban'd Turk

Beat a Venetian and traduc'd the state,

I took by the throat the circumcised dog,

And smote him - thus.

Then he reads it again to himself. And again. And again.

"I'm stumped," he finally admits. "I mean, I see some connection, obviously: Othello stabs himself after this, right? But every second Shakespeare play ends with someone killing themselves; half of Roman history, too. The boy could have chosen a hundred other passages about suicide to underline, or none at all - so why this one? And why would he want to kill himself in the first place?"

"You're not looking, Lestrade." Sherlock's voice has that harsh edge to it again. "Look. At all the things in his pockets. At the things he wrote in the margins of the book. At what the other boys and teachers said about him. At what they didn't say. And then look again at that speech. He underlined it in purple. It was his favourite colour; it's all over his phone. That and the knotted string - they're his note."

"You really are a nut-case," Phil laughs. "A quote from Shakespeare and a piece of string a note? The string is nothing - just rubbish he was playing around with, the way boys do. If you'd ever been half-way normal yourself, you'd know that, Freak. And the book's only there because he had to read it for class. This is a school. The play was an assignment, that's all."

Sherlock looks at him witheringly.

"What sixth-year teacher is going to try to teach Othello, Anderson? A Midsummer Night's Dream or Julius Caesar, possibly, though it's far too early for the average idiot like you. But Othello? No one would try to get a classful of ten-year-olds to read that. The play was in his pocket because he'd chosen it himself. Because he liked it."

"Liked it? A ten-year-old kid? He couldn't even have read that on his own, not without a teacher talking him through it. And you can't tell me he was paying attention to it, anyway; he was bored to death by it. Look at it, all he did was scribble all over it. It's a mess!"

"You really should find a brain for hire sometime, Anderson. Marginalia isn't exactly a new phenomenon; not everyone thinks books should be kept as blank as your mind. There are stains on those pages, as well as writing - gravy and juice. He wasn't doodling in class; he was writing in the dining hall, at meal time, because he was thinking about a problem and needed to get his ideas down on paper, and this was what he had with him."

"Oh, sure. Just what every sixth-year kid does at school dinner: makes notes in the margins of a Shakespeare play. Right. Tell us another one, Freak."

"What did he write, then?" Greg asks. "It looks like nonsense to me, but I suppose you're going to say it means something."

"Of course it means something. The diagrams are illustrations of the two-slit problem and Schrodinger's box. And he'd worked out a derivation of the equations for special relativity."

"Special relativity!? You mean, like, Einstein!?"

Sherlock shrugs again.

"I've deleted most of the details now - they didn't prove very useful - but it's not that hard, once you find the right place to start. He might have got a prompt off the internet, or he might have worked it out for himself. General relativity's the more challenging one."

"What's the point of all this?" Sally explodes. "What does it matter if the kid was so smart he was playing around with Shakespeare plays and fancy maths and knots and Morse code? You haven't said a single thing that explains why he would have wanted to off himself! And without that, all your stains and chips and footprints and stuff in books could be explained a hundred other ways; they don't have to add up to suicide at all. This boy had no reason to kill himself. A good home, a wonderful school, a star athlete, a brilliant student - all his teachers with nothing but praise for him - there's no reason in hell why he should do such a stupid, pointless thing."

"As usual, Sally," Sherlock says, "you're failing to look at the evidence and ask the right questions."

Sally glares at him. Greg sighs again.

"What questions should we be asking, then?" the D.I. asks, wearily.

"John," Sherlock says, "please tell the Detective-Inspector what questions he should be asking."

John suppresses a sigh of his own.

"Why don't you do it, Sherlock?"

"I asked you to."

"I'm not sure I know what you're thinking of."

"Yes, you do."

They hold each other's eyes for a long moment. Of course it's John who gives in.

"I suppose, Greg," he says, his voice as neutral as ever, "Sherlock thinks we should be asking whether, for all the accomplishments Sally has pointed out, anyone actually, you know, liked this poor kid. Whether he had any friends."

"I did say," Phil says, stridently, "that he was an annoying little swot who was probably done in by a jealous teammate."

"Not quite the same thing," John says, while Sherlock throws back his head, stares down his nose at Anderson, and snorts. With his dark, windblown hair and the steep, sloping angles of his brows and cheekbones, the effect is not unlike a wild stallion considering whether or not the time has come to rear up and trample under his hooves the shambling human creature who has just dared to come within his reach.

"Precisely," he says.

And then he puts his hands in his pockets and turns away, looking back down at the boy again. They all stand quietly, looking too, while the rain drums mournfully on the canopy overhead, and the hauteur in Sherlock's face slowly fades to something remarkably like regret.

It's a long time before he speaks again, and when he does, his voice is quieter and more remote than Greg can ever remember hearing it before.

"You asked why I said you wouldn't be able to stop this from happening again, Lestrade. The answer should be obvious: there are only two possible approaches that might forestall another child in similar circumstances from taking similar measures, and neither of them actually works very well. You might achieve temporary success with one or the other, but eventually the method will break down, and the result will be another" - the lines of his face tighten a little, and something flutters for a moment in his throat. "Another Gareth Sheldon-Jones."

His shoulders hunch up inside his coat. He continues to stare, as if lost in thought, at the remains of what used to be a brilliant ten-year-old boy.

John watches him uneasily.

"Um, Sherlock?" Greg says, after a while. "That's a bit cryptic. If it's all the same to you, I'd still like to know why you think this will happen again. Who it's going to happen to, and where. And if we can work that out, surely there's got to be some way we can stop it?"

"Two ways that might, but they won't actually work, he says," Sally mutters.

And Sherlock surprises everyone by turning around and saying, "That's right, Sally." Then he digs his hands deeper in his coat pockets and turns back to the child's body again.

Greg is just about to say, "Right, that's it," and call for the techs to start the clean-up when Sherlock answers his question.

"Somewhere in the world, possibly somewhere in this country, right now," he begins, his voice so low that Greg can hardly make it out, "there is undoubtedly another boy like this one. You might not think it, but the statistics do, in fact, suggest it. Very likely more than one, though the probabilities of them meeting when they are still young enough actually to be of some use to each other are, unfortunately, quite slim. The first approach to preventing - this" - he frowns down at the body on the ground - "from happening again is to teach that boy not to care what other people think." There's a pause, and then he adds, "Of him."

Everyone goes very still.

"You might start by telling him that what he already knows about himself is, in fact, true: that the way his mind works, the abilities and interests that seem perfectly normal and natural to him, do indeed make him so different from the others that he will always seem quite alien to them. Whether they're his own age, older or younger, boys, girls, men, women, it won't matter; they may at times find him irritating, annoying, infuriating, intriguing, fascinating, or even quite useful on occasion, but none of them will ever actually think of him as anything other than what his schoolmates already call him, behind his back and to his face, day after day, relentlessly - a freak."

An odd little noise comes from somewhere in the back of Sally's throat. Greg hears it, but can't take his eyes off Sherlock. John is focused only on his friend's face - the whiter-than-white skin; the blue-grey eyes that might be looking at something a million miles away, or at nothing at all - and his voice, which though still deep has lost its usual rich timbre and seems to be coming from a different body altogether. A smaller body, John thinks; younger and smaller, taking smaller, shallower breaths. John is watching his friend so intently that he's started to breathe the same way himself.

"If you want to give this method its best shot at success," Sherlock continues, "don't try to hide the truth. Tell the boy, when that word first disturbs him, that he never will be able to fit in with the others, no matter how much he might think he wants to. They will always resent and despise him for the differences, even though he can't help those things about himself, and didn't choose them. Tell him there's no point in trying to hide what he is, or change it. He will inevitably fail, and the failure will be more - difficult" - he hesitates for a split second before the word, as if choosing it carefully - "than simply accepting the truth in the first place would have been."

He pauses. Everyone is staring at him, hypnotized, but John isn't sure that Sherlock is even aware of their presence.

"Teach him," Sherlock goes on, "that the only way to avoid the - " (he hesitates again, blinking, then takes a deeper breath and goes on) "the - pain - which might seem, to the undefended mind, unbearable, is not to allow the opinions, thoughts, or feelings of others to influence his own in any way at all. Tell him to resist the temptation to see himself through their eyes, to be the circumcised dog to their Venetians. Instruct him that his feelings are of no advantage to him, that they can only hurt him - as he will already have discovered for himself in any case. Train him to hold himself above the others, where they can't reach him, and to embrace his own mind as his best and only friend - since that's all he'll ever have, all he'll ever be able to depend on."

He stops then. Except for the sound of the rain falling on the canopy, there's absolute silence - a silence that seems stretched so taut Greg thinks it might snap, entirely of its own accord, at any moment, setting off some cataclysmic reaction that will bring the nearby buildings, the school, the surrounding village, - hell, the whole adjoining city, counties, country, maybe the whole world - crashing down around them. Sherlock is Mycroft's brother, after all.

It's John who breaks the stillness, though, clearing his throat again.

"But that's not true," he says, gently.

Sherlock blinks. His eyes move back to his flatmate and rest on him with a startled expression that fades gradually to something like relief.

"No," he agrees, and his shoulders seem to relax, making the top of his collar drop away a little from its protective stance around his face. "Not, as it turns out, always absolutely true. And, as I said, that approach doesn't really work as well as one might wish, anyway. But for boys like Gareth, it's probably still the best first line of defence."

He seems to be speaking to John alone.

Sally is gripping her arms tightly around herself, trying to keep from shaking. An unaccustomed sensation of something she doesn't want to acknowledge is building up in her eyes. She lifts her chin defiantly.

"Just boys?" she asks. She's going for cool, but there's a quaver in her voice that she knows everyone can hear.

Greg is surprised when Sherlock answers.

"Girls too, naturally." His voice is flat and expressionless. He doesn't look at her.

Then he turns abruptly and strides away, his coat billowing around him. John follows, breaking into a half-trot as he tries to catch up with his friend.

"Jesus Christ," Greg mutters, shaking his head. "Jesus bloody Christ."

Sally stands there, trembling. She would give anything - anything - to be able to pick the child's broken body out of the flowerbed and breathe life back into it again. She never wants to see another one like this. So she lifts her chin again and calls after the detective, "Oi! Oi - you!"

He doesn't stop. She screws up her face and tightens her fists, as if it's costing her a tremendous effort to change gears, and tries his name: "Sherlock! Stop! You said there was another way. What is it?"

He doesn't break stride.

John does, though. He stops and looks over his shoulder at Sally for a long moment, then turns and walks back to the little group still standing beside that small, pathetic shape lying among the broken daffodils at their feet. Somehow the way the doctor is moving makes him look taller than usual, and quite threatening. His hands clench and unclench as he moves, as if he'd like to hit something. Or someone.

Sally doesn't think he'll hit her, but she flinches a little just the same at the hardness in his jaw and the flint and steel sparking in his eyes. He's not just a doctor, she remembers then; he's a soldier, too. It's the first time she's ever really thought of him that way.

"You don't know, Sally?" he says, harshly. "You really, honestly don't know the answer to that question?"

She stares at him and swallows, hard. Drops her eyes, trying not to let the entirely unprecedented and demoralizing tears overflow. Looks at John again. Shakes her head.

John stares back at her for one long second after another. She finds herself wondering if he's ever actually killed someone, and thinks he might have.

Then his face begins to soften, and she knows he'd only have done it if he had to, to protect someone else who deserved to live more. When he speaks, his voice is the doctor's again - as gentle as ever, but weighed down with a weariness that reminds her that doctors, like soldiers, can't always save the lives they're fighting for.

"The second way," he says, "is to teach the others not to call people freaks."

Then he turns and jogs after the dark-coated figure already disappearing into the rain-soaked night.