Title: In Which Sherlock Attempts to Eliminate the Impossible

Category: Harry Potter/Sherlock crossover

Genera: General

Rating: T (mentions of child abuse)

Words: 2329

Characters: John Watson and Sherlock Holmes.

Source: Inspired by esama's various HP/SH crossovers…especially "Potter in Baker Street" and "Whispers in Corners".

A/N: See time line information at the end of "New Tenant" for more details.

0o0

John was less than surprised to find his flat mate in deep contemplation over their new neighbor a few days later. What was shocking was that the detective had yet to pin down the kid's life story.

"It's very bizarre," Sherlock said idly, letting his thoughts flow to his willing audience, "Classic signs of PTSD, mental trauma, and child abuse, and yet he acts in a way that says he came to terms with it all years ago."

"Child abuse?" John asked, wondering how the detective came to that conclusion and a bit worried about the kid.

"Yes, isn't it obvious?" Sherlock remarked offhandedly, gesturing vaguely. The sleeve of his shirt rode up, revealing what appeared to be nicotine patches on his arm. John's eyebrows shot up—clearly, there was more to the new tenant than met the eye, if it had his flat mate considering him a three-patch-problem. "Keeps his back to the wall, notes all the exits, prefers to stand in smaller, more enclosed spots," Sherlock continued, "Of course, it's all overlaid with whatever war experience he's had—"

"What?" John cut him off. Yes, he'd thought the kid might have enrolled in the military, but actual combat?

"War experience, John, do keep up," the detective frowned in his direction, "Front line too, from the looks of things. Oh, you cannot possibly be this blind!" he exclaimed in exasperation at the doctor's blank look. He rolled into a sitting position on the couch in one graceful move, "His defensive stance, John! The way he positions his feet—perfectly balanced to absorb any sort of blow with minimum difficulty. The way he twists his torso when talking to people so that child of his is always shielded by his body. The way he judges every individual he meets for potential threat capacity. A rather unconventional war by our standards, too," he trailed off on a tangent, "Seeing how he considers me to be the greater threat, when anyone with his training would easily see that you have much more combat experience and therefore are a much greater physical threat than me."

John blinked at the unexpected compliment, though he doubted that Sherlock had intended it as anything more than a mere statement of fact.

"But none of that's important," his flat mate continued, oblivious to John's once again rising eyebrows. "The problem is that he's wrong!"

There was a rather long pause, in which the detective flopped back into his reclined position on the couch in pure annoyance and John attempted to figure out where on Earth Sherlock was going with this train of thought.

"Wrong?" the doctor finally asked, hesitantly.

"Yes!" Sherlock replied, practically pouting as if the universe had decided to go out of line purely to spite him. When it became obvious that John was once more lost in the maze of logic, Sherlock managed to look down on him while lying flat on his back and continued the thought. "Wrong, John. He left a highly abusive household a year ago and yet he's far too well adjusted for that short of a time frame. He—"

"How do you know it was a year ago?" John interrupted.

"Scar on his neck. A little over a year old, and the given the position, depth, length, has to be a belt buckle. Stunted growth shows that he's still recovering from malnutrition and controlled starvation—though of course, some of that is from the war he fought in—but he's not emaciated, so he's had some amount of time to put on a little weight. Plus, he's eighteen, year ago would have been summer, and then he left for boarding school—obviously, he wasn't going to go back to that household afterward, especially with a child in his charge now."

"His son?"

"No don't be ridiculous, John, godson if anything. And clearly he must be somewhat responsible and reliable as someone was willing to name a teenager a godfather. Especially one with so little official schooling."

"What?" John was getting steadily more lost.

"I obtained the background information he gave Mrs. Hudson," Sherlock explained, and by 'obtained', John correctly assumed the detective meant 'stole'. "There wasn't much to go by, just his name, really—Harry James Potter. No previous employers, no parental permission notes, and most interestingly, no school records. Mrs. Hudson in quite a capable landlady, the only reason she'd take him on with so little information is if her conversations with him convinced her of his character."

"So he isn't to be trusted?" John asked, suddenly more wary and remembering the odd feelings he'd gotten from the kid on that first day. Sherlock shot him a Look.

"To pay the bills on time, keep his flat in reasonable shape, and not blow the whole building up? I don't think she could have chosen a better person." Sherlock replied in a slightly ironic tone, indicating that he was more aware than he pretended to be over the fact that he definitely did not fit those requirements. "With not breaking into the other flats and stealing items of worth? He's not the type—well, for stealing, that is. I'm sure if we give him strong enough reason to believe that he and his child are not safe in the premises, he'll be snooping around sooner or later. With our lives and our secrets? Well, when do you ever trust the neighbors with those? That one depends entirely on what impression we make on him."

"So that lack of school record?" John attempted to get the stream of deductions back on track.

"Ah yes. Well, I didn't have anything more than a name, but a name is all you need, sometimes. I hacked Mycroft's data base—took me a couple of hours, he's updated his security again—and ran the name against all the people in Britain. Came up with a 'Harry James Potter', born July 31, 1980 to ones James Potter and Lily Potter nee Evans. Both of his parents were marked 'deceased' a little over a year later. Grew up in Surrey, raised by his mother's sister and her husband, along with their child. Found school records, along with some reports of child neglect and potential abuse (all ignored, interestingly enough), which end when he reaches eleven. No signs of a secondary school, no A-levels, driver's license, nothing.

"I ran his parents' information against the data base. Absolutely no records of his father aside from that birth certificate. As for his mother…nearly the same story: typical childhood, and then vanished at age eleven. No marital record, voting record, A-levels, etc. The excuse offered for Lily Evans' withdrawal from the public school system was that she was accepted into an exclusive boarding school in Scotland. There was no reason given at all for that of her son's.

"Now, this boarding school—which both mother and son attended, and we can assume the father did so as well—there aren't any records of it. Oh, there are, obviously, boarding schools in Scotland, but none of them ever accepted a Lily Evans or a Harry Potter. And this is Mycroft's data base, and while I hate to compliment my brother, the reason I was using it to begin with was that it has the most complete records of everything in the United Kingdom. So not only does it have the normal schools, but also the schools designated for high profile individuals' children. And yet…nothing. So what does this tell us?"

He paused in his monologue to look at John. The doctor thought for a minute.

"That Mycroft doesn't know everything?" he hazard, fairly sure that this wasn't the correct answer or the one his flat mate was looking for, but unable to resist.

Sherlock let out an exasperated, why-am-I-stuck-in-a-world-full-of-idiots sigh, but he couldn't quite hide the small grin that John's comment evoked.

"Put together the facts, John! Children—and not just these two: after I found this discrepancy, I ran the entire data base and found many more that fit the pattern—vanish from society. No one protests, which implies that their parents, at the very least, know where they're going. Almost all the records claim an excuse of going to an 'exclusive boarding school', which research has proved doesn't exist. However, we can gather that they're getting an education, merely by our new neighbor's actions and statements: not posh, it's no 'finishing school', but definitely educated. Not high profile individuals, either, just perfectly normal families. Some of these children reappear seven years later, with tailored school records that say they took an equivalent of A-levels, but most remain invisible to the world."

John frowned, remembering the case they'd had the previous week. "Do you think—?" he began.

"No," Sherlock interrupted. "I already hacked their files, and then," he grimaced, "Called when that failed to turn up the necessary information. They don't know anything about this."

That was interesting. John mentally reviewed Sherlock's deductions, trying to figure out where to go from there.

"Where's this 'war experience' coming from?" he asked finally, "There aren't any wars I know of that would allow British children on the front lines."

"Well, it wasn't an official war—I'd gather that hardly anyone knows about it, outside of this vanished society. It took place in the United Kingdom (our neighbor's never been out of the country), and probably has a great deal to do with the enormous media cover-ups that Mycroft's been doing for the last two years or so."

"Media cover-ups?" John asked, wondering when his life turned into a giant conspiracy theory.

"Yes John, do be a bit more observant. Or did you not notice that there's been an inordinately large number of gas leaks these last few years."

Actually, John had noticed, thank you very much. He had just attributed it to the steadily falling standards and general corruption in businesses, as opposed to a mass scheme of Mycroft's. He supposed he should have known better.

"At any rate, there was an underground war going on in Britain—fought by this missing society of ours—"

"How do you know that it's a missing or hidden society? That once they get out of this school, they don't just go live on their own or change their identities and re-enter the regular world? Or even move to a different country?"

"If it was anything but hiding in mass seclusion, Mycroft would have picked up on it." Sherlock sounded thoroughly annoyed at having to compliment his brother again. "And it's definitely a society. Our neighbor's maintained polite manners and the ability to interact with complete strangers comfortably. Those traits tend to vanish when one lives in complete seclusion or interacts with the same small group of individuals all the time. Yet why hide themselves from the world? And how are they doing it? The data shows all the supposedly hidden cults from Britain, yet they don't have anywhere near enough people to account for the number that have vanished."

"So, there was a war, here in Britain, which none of us knew about—except for maybe Mycroft—and in which they allowed kids to fight on the front lines? That's your conclusion?" John was a bit hostile to the idea, though he didn't doubt Sherlock's deduction.

"It would seem like. Which of course brings us back to the fact that our new tenant is wrong."

"Yes, care to explain that without wandering off on a tangent this time?"

"He lived in an abusive household, fought in a war that ended not even three months ago…and he's perfectly adjusted. Completely fine. Oh sure, he's got the physical reactions and general paranoia that have yet to vanish, and probably won't for years, but other than that? No obvious mental trauma. Think about it John! You were back from Afghanistan (not counting the time in the hospital) for a few weeks before I met you. And I could tell right away that you were a soldier still adjusting to society from the way you carried yourself, spoke, and your reactions to my comments. You still flinch at gunshots if you're not the one firing them. Your eyes trace the sky when you hear a military plane fly over. And you've been back for two years now! And yet our new tenant, who only got out of his war a few months ago, lacks all of this."

"How can you tell he was even in a war, then?" John asked, trying to get the subject off of his time in the army.

"Oh, I probably wouldn't be able to if it wasn't for that baby of his. He's very protective, notice? And it brings out all of the training and instincts that could only have been obtained from combat. Other than that though…John, when have you ever heard of people going through traumatic experiences without flashbacks afterward?"

"So that's the problem, then?"

"Among other things. No one survives what he's been through without some lasting mental damage. And yet…nothing."

"So where does that leave us, exactly? We've got what? A secret society that hides itself from the rest of Britain—including your brother, unless he does know about it and for some reason hasn't put in his is data; children vanishing at age eleven or thereabouts, and the possibility that others are born into this society; a war that the rest of us missed because Mycroft's been covering it up; and a perfectly fine neighbor who is only eighteen, fought in a war, survived an abusive childhood, and has a baby of his own to take care of? Sherlock, we've seen a lot of crazy things over the last year or so, and I know your deductions are correct, but…"

John trailed off shaking his head with a sigh. His flat mate didn't answer, eyes glazed and fixed on the ceiling.

"I'm missing something," Sherlock mused, hands steepled under his chin, "Something important. Really important."

0o0

A/N: So, obviously, what Sherlock's missing is the magic. As for the whole "Harry is well adjusted" thing: it's from an idea that I've been tossing around, that the Deathly Hallows fundamentally changed Harry's nature when he came back to life. Basically, they couldn't risk having someone be the Master of Death and mentally unbalanced at the same time. So they…fixed him. Completely cleared up any trauma he had experienced and wiped it out. They also mellowed out his personality and made him a very accepting individual. Possibly not the best thing in the world, but it's probably the path that would cause the world the least harm.

Brownie points if anyone picks up what Sherlock and John keep hinting at. (hint: you need both stories is this series so far).