Disclaimer: I own nothing but the general plot and OCs

I'm seriously amazed and thankful at the crazily supportive and interested response I got in response to chapter one of Mystery Child. So much gratitude here! I loved everyone's guesses and curiosity at what had happened to Harry.

Compared to last chapter I feel like this one is lacklustre and is also shorter, but no matter how much I poked at it this chapter refused to go anywhere after a while so I ended it here and decided to try again next chapter.

Also in terms of season 3/4 canon, I'm not getting rid of it in its entirety but I'm definitely tweaking significant aspects of it. This fic isn't just gonna be Sherlock and Harry and John plus some of the other characters popping in, with cases getting a summarised mention. Once Harry has settled in, the formula of the tv series will be reasonably similar to the way I approach the writing.

Having said that, the way the writers write Sherlock is by taking inspiration from some ACD stories massively and constantly sprinkling references to other ACD stories throughout, combined with a fair bit of modern originality. I obviously won't be doing anywhere near as masterful a job but that's basically my plan, with some original cases, some ACD inspiration, some changes Harry's presence would cause and some purely magical focussed bits.

Thank you so much for awesome reviews, as well as favs and follows! Let me know what works, or what doesn't work for you, as well as any prompts for scenes you'd like to see.

Chapter 2

Sherlock was sat sulkily cross legged on the sofa. He had been in that exact position for five and a half hours, after creating the most god awful sounds on his violin for two. John sighed as he put the kettle on.

"Come on, Sherlock. I thought you were amenable to the idea of Harry coming to live here. We'll just have to be careful about which experiments you leave lying around. We'll need to buy him some clothes, and make sure he gets regular meals. Find... something... For him to do all day even if it's spending time with Mrs. Hudson. It won't be too bad."

Sherlock just snarled wordlessly for a moment in order to emphasise his next assertion, "I'm not making any concessions for that insufferable child. My experiments are staying right where they are. I'm not shopping, or cooking or cleaning. I am not altering my timetable to suit the whim of an obstinate brat. The Work is all that matters to me and he is not getting in the way."

With that he dramatically lay down and faced the back of the sofa with a flip of his coat tails. John chuckled at the physical melodrama.

"I know that's not what your real problem is, Sherlock. But really what did you expect? Of course Mycroft was going to want to meet the child that was important enough for you actually go to him about and deign to ask a personal favour. Surely it's a good thing that they get along and Mycroft has agreed to this, even if it's just on an interim period."

Sherlock merely made a disgruntled noise and ignored John, who rolled his eyes.

"I thought you said Harry was tolerable. It's not like he's going to be a spoilt tantrum thrower- unlike someone else who lives here," he added under his breath.

"Besides, I have it on good faith that Harry likes Mycroft less than Mycroft likes Harry."

Sherlock hummed thoughtfully.

"I believe the exact words were, 'a controlling man who feels the need to know absolutely everything about everyone, even things which are none of his business, and is determined to prove he is the smartest person in the room, when he really just needs to stop congratulating himself'. All that from one ten minute meeting," John only half made up - well that was the gist of the kid's comment. Thereabouts anyway- John figured he couldn't exactly be expected to rattle accurate quotes from non-famous people off the top of his head like Sherlock could.

There was a pause before Sherlock reluctantly admitted, "he is less brain dead than most children his age."

"There that's practically an admission of his genius," John replied with a grin.

"He's hardly a genius, John. His skill set doesn't lie in his ability to do advanced calculus or particle physics. He was a soldier. He knows how to deal with people and danger."

"Well he's going to need all his skills in dealing with people to put up with you when you're bored, so I'd say that's a good thing," John teased, as he switched some crap TV on.

"Are you going to watch Jeremy Kyle?" Sherlock asked curiously, peering over his shoulder at the TV.

"We agreed not to after last time."

"Humph," Sherlock went back to looking at the back of the sofa grumpily, as as John calmly sipped his tea.

Molly was sipping her cup of coffee and observing Sherlock out of the corner of her eye in what she thought was an inconspicuous manner. John shook his head despairingly at the two; even after two years of being away she was still caught up in mooning over a man who was 'too busy for sex, let alone a relationship' according to himself, and Sherlock was still a right bastard who had no problem with manipulating Molly's affections to his own advantage before callously dismissing her. It was like he'd never left sometimes.

John could see that Sherlock was close to a temper tantrum. It had been building up all day as the time ticked onward for them to pick Harry up from the hospital and Sherlock came no closer to discovering the significance of the two tattoos on the young boy. Finally Sherlock slammed the lid of John's laptop down and pushed it aside with a snarl.

Molly jumped in surprise, sloshing coffee down her brand new shirt and John quirked an eyebrow.

"This doesn't make any sense, John!" Sherlock snapped, glaring at John as though it were all his fault.

"No luck then?" John was a just a tad amused at Sherlock's aggravation with not knowing something or even how to get his hands on the information.

"There's no obvious reference to either tattoo anywhere on the Internet, and according to police databases, it's not connected to any gangs. It's not from any culture that I could find, nor any religion."

"Well maybe that's the point. He doesn't belong to a culture that you could find on the Internet or any obvious books. You're probably looking in the wrong places," John sensibly pointed out. Sherlock just pouted at the idea of losing for once.

"Why don't you have a look at his file?"

Sherlock's head snapped up, "what file?" The doctor sighed in exasperation.

"The file Mycroft gave us after he did a background check on the kid. After he agreed to sort out the paperwork to let him stay with us as a favour. Remember?" John rifled through the files on the countertop as he talked before he came across the correct one and handed it to an impatient Sherlock.

The detective snatched it out of John's hand and opened it up eagerly, only a little sore at having to rely on information his brother had procured for him.

"Parents died in a house fire," Sherlock scoffed, "hardly as accidental as the file states."

Grandparents died before he was born in a house robbery gone wrong- unlikely to be true- cancer and suicide shortly after. Bla bla bla, boring. Average to low grades, low attendance, clearly a result of the abuse. No previous doctor or hospital visits, no previous inoculations. Went missing a few months ago, reported by the school. Upon police questioning, relatives were arrested on suspicion of murder after traces of the boys blood was found underneath the stairs along with a bed. Trial ongoing.

"There's nothing in this file of any relevance," Sherlock huffed, and threw it back to John. John merely shrugged.

"His birthday's next week. He'll be nine," John offered.

"Oh brilliant, genius John, you've cracked the case of his mysterious tattoos. It's all about his birthday," Sherlock retorted scathingly.

"There's a nine year old with tattoos?" Molly gasped in surprise.

"An eight year old with tattoos, Molly. His birthday is next week, do keep up," he rolled his eyes.

Although he'd claimed to file was of no relevance, it did share one important detail; Mycroft was as in the dark about Harry as Sherlock was. The file described a plain, boring, predictable mistreated orphan who went missing. Not a child soldier. No doubt Mycroft had gleaned as much as Sherlock had from his ten minute meeting with Harry, and decided to place the boy somewhere he could keep a close eye on him.

Sherlock's offer was probably the perfect opportunity; an excuse for increased surveillance on his little brother and on Harry in one go.

Sherlock's phone dinged as a text came through.

You need to pick up Harry ten minutes ago -GL

Mycroft's here as well -GL

Sherlock growled under his breath about insufferably nosy siblings, threw his coat and scarf on and dramatically exited the building with John trailing behind.

By the time Sherlock entered the hospital Lestrade had texted a further eight times and called twice. Apparently he found Mycroft creepy. John couldn't disagree.

Mycroft was waiting out front for them, smiling with polite patronisation.

"Brother, late to pick up a child in your care isn't the best start."

Sherlock brushed past him rudely, "you were here. It's not like anything would happen to him."

Mycroft sighed, "Sherlock, at least try to act responsible. You'll be in charge of another person's life constantly now. You can't just delete him when he becomes inconvenient or boring."

"I've had a pet before Mycroft, I know what's required of me."

"Sherlock!" John hissed. Sherlock had the decency to look contrite for a moment. Just a moment though.

"Fine. If it's what you both want to hear to make yourselves feel better; I promise to make sure he's fed and watered and that he sleeps well after he's tucked in with a bed time story and a glass of milk once he's been given a good night kiss," he mocked. Mycroft heaved a long suffering sigh.

"I've bought him a new wardrobe, and I've made some minor alterations to the flat to make it more child friendly. I'll enrol him into a decent school and arrange transport too, starting in two weeks. If he lasts that long. He'll need to be tested to see where he is along his education."

Sherlock looked furious at the information that Mycroft had changed his flat in anyway.

"Thank you for your sincere care Mycroft, but I can find a school for him without your assistance in the matter. Good day brother," he spit venomously over his shoulder.

"Sherlock, just remember. We know very little about him and he seems adept at lying. I wouldn't get attached to his presence if I were you."

Sherlock sneered and ignored him resolutely. Mycroft arched a brow at John who was suppressing a grimace. Sometimes he really couldn't stand the things Mycroft said to Sherlock.

"Good day, John," Mycroft nodded to him and then left, umbrella swinging by his side.

There was a heavy silence as John and Sherlock walked side by side, Sherlock avoiding eye contact with John in the hopes of putting off a dull conversation about his feelings or some other equally boring sentimental drivel. He sighed internally when the doctor cleared his throat pointedly.

"About what Mycroft said..."

Sherlock stopped abruptly and turned to face John.

"Mycroft has imparted with a lot of words in my presence, very little of which I listen to and even less of which I haven't deleted. You'll have to be more specific, John," Sherlock replied, being purposely belligerent. John gave Sherlock a knowing look.

"About not getting attached to Harry being around," he hesitated, trying to find the right words. Sherlock butted in before he had the chance.

"A sound piece of advice. Of course, he needn't have wasted my time telling me what I already knew, but then my brother does so enjoy doing that." John hated it when Sherlock wore that impassive mask of his. It was always when he was determined not to act like a human being with emotions. Just a cold logical machine. It was when he was resigned to disappointing John with what he was about to say.

"Look, there's nothing wrong with getting close to people, Sherlock. You said so yourself that the kid isn't as oblivious as most people, I don't see what good can come out of this if you insist on keeping him at arms length when he comes with us. You can't just go through life acting like you don't care about anyone," John ranted, becoming more frustrated with the detective as he spoke.

Sherlock, ever the stubborn man, refused to make eye contact and his expression didn't even flicker.

"Of course I can, John. It's far easier than one would expect. I have said so before, but perhaps you need a reminder; sentiment is a weakness. It is a dangerous flaw that is easily exploited by enemies and I am not going to allow a physically weak child with average wits to be my Achilles heel. Getting attached to that child would not only be illogical but stupid.

"He's coming to stay with us because for now he's my one and only source of information on an entire society that I had no idea existed, and he will leave when I have learnt all I can from him. He isn't coming to stay with us so we can be raise him and play happy families. Love is a distracting factor which might throw a doubt upon all my mental results.

"He is and will remain a means to an end and as such, yes John, I will be keeping him at arms length. I suggest you do so as well lest you fall prey to dangerous emotions like love," Sherlock spoke the last word with heavy contempt, but besides that his voice and face remained cold and emotionless.

Sherlock watched silently as John struggled with his disappointment, anger, and various other cocktail of feelings that confused the doctor.

"And what about me? Do you keep me around because I'm a means to an end, making sure you never care at all because I'm just your stupid flat mate and God forbid you actually give a damn and someone hurts you for it. Because that's a very sad way to live Sherlock. Or do you care about me because I'm not physically weak so that's ok? And what about if I was hurt and became disabled, or infirm. Would you cut me off? Delete me from your mental hard drive because I'm no longer convenient?" John's eyes were hard, and there was a clear current of anger underneath his quiet tone.

There was momentary pause, in which John decided he didn't want to know the reply to that and continued walking. As such he didn't hear Sherlock's murmured answer.

"I cannot afford another Achilles heel like you."

John stood behind Harry on the landing just outside their flat, with the door mostly closed and various crashes and bangs reaching them from inside.

"No, no, no! It's all wrong in here! That doesn't go there, and- oh, for- NO! He's ruined it. It's all ruined. All my experiments!" Came Sherlock's litany of aggravation from inside, as the bangs increased.

Harry turned his head to glance with mild concern at John, and bemusedly asked, "is he okay?"

The shadenfreude John felt on the inside was mostly hidden from his features, but not entirely. He shrugged in reply, "he's just throwing a tantrum because his older brother cleaned his room before he was done playing. He'll be fine once he's had a sulk."

"Right," their new...kid? replied, his tone dubious.

Just in time for the cessation of noise inside, John's phone began to ring. Looking down he saw Mycroft's name, and with a sigh, reluctantly answered.

"John, how are you finding the rearranged flat?" The older man's smarmy voice enquired.

"Yeah, well Harry and I haven't actually walked inside to see it yet, but somehow I don't doubt you already know that."

"Hmm, quite. Let me know if anything is missing from your new ward's possessions, I did specify age appropriate toys and reading material but then the Holmes' standard is often so very... cerebral shall we say, compared to the general masses. It can be difficult to accurately predict just how much a person won't understand."

"Why do I get the feeling I'm the one being called an idiot and not the kid? Whatever it doesn't matter, what do you really want, Mycroft?" John huffed a little, his patience running thin.

"Very well, lets skip the pleasantries. I've ensured that Harry has a week to settle in and become accustomed to Sherlock before any officials come knocking for my little brother's expertise. Perhaps by that point he'll have come to some sort of resolution about the mystery child, and we can move on from this silliness."

"You don't think he'll be interested in Harry for long enough to start school do you?" He accused, feeling irritation build at the casual dismissive callousness that both Holmes' were prone to.

"I think that Sherlock will not find the addition of a child in his life to be fulfilling in the way so many claim. My dear little brother adores the spotlight, John. I can't imagine he'd appreciate having to share that with anyone, and children need attention. I think Harry won't last long."

"Well I think you're wrong. I think Sherlock is a lot more capable than you give him credit for."

"Perhaps. I give it two months at the latest, and I'd love to be proven wrong this time. Goodbye, John."

"Prick," John muttered, despite there being no one on the end of line.

"Can we go inside now?"

John jumped, as the young voice reminded him of Harry's presence. He was momentarily flustered at what Harry had almost definitely overhead, but he soldiered past the awkwardness and cleared his throat.

"Ah, um- oh, inside! Yes, yes, lets get you settled in."

Walking inside to the living room, they were met with the sight of Sherlock bent over with his head stuck in the fireplace surrounded by books and papers strewn on the floor as a result of his fit.

"Sherlock? What are you doing in the fireplace?"

"Mycroft has had plenty of time to get his fat paws all over the place while he wrecked our flat with his redecorating," he spat like it was a dirty word, "I'm sweeping the place for recorders of any kind."

"Ah," John acknowledged, taking a proper look at the place. The flat was probably tidier than he had ever seen it, even with the mess on the floor.

The carpet had been replaced and no longer had the chemical stain in the right corner that had infuriated John at the time it had happened, but after a while had just become a feature of the flat. There was a third chair by the fire, all the shelves were stacked neatly, and John noticed a small shelf close to the bottom which held non fiction and fiction books Harry might enjoy. The sofa was fabric now rather than leather, as well as slightly bigger, and all the smaller cupboards and shelves that were used for storage - mostly by Sherlock -had been replaced for something far more ergonomic and efficient.

The new coffee table in front of the sofa had a section underneath it which contained various board games and a couple of books. On the table that was placed closer to the window- also new and larger than the one before- lay a new phone and an iPad mini, with a small note that said 'For Harry' in Mycroft's ridiculously elegant handwriting.

"An iPad? That's a bit excessive isn't it?" John questioned Sherlock, who was now pulling the chairs apart and inspecting all the cushions.

"My brother might scoff at the idea, but he's petty enough that it would delight him if Harry favoured him over myself."

John almost made a dry comment about Sherlock claiming that Mycroft was petty as though they weren't just as bad as each other, but a quiet voice interjected before he could.

"What's an iPad?"

John jolted as he remembered Harry's presence, already caught up in the usual tempo of just being the two of them in 221b that he had forgotten the boy was there entirely. He made to reply, since Sherlock had already demanded on the way to picking Harry up from the hospital that the doctor was in charge of the 'stupid questions', but to his surprise Sherlock was the one to reply first.

"Here," he stood up and walked over to the table, throwing the phone to Harry who caught it with impressive ease in one hand, "I'm sure mine and John's numbers are already saved. Send me a text."

Harry looked blankly at Sherlock, and then down at the mobile in his hand. He hesitantly pressed the home button and blinked as the screen lit up his wary and baffled features.

He flipped the phone around in his hand and studied the edges, experimentally pressing the volume buttons, the sleep/wake button and the silent mode switch. It became immediately obvious even to John that Harry had no idea how to work an iPhone.

"There are only four buttons. Where are the rest of them?" The green eyed child asked, frustration creasing his brow.

With his hand held out in silent demand for the phone to be thrown back to him, Sherlock watched Harry with keen curiosity, his blue grey eyes practically glittering as his thoughts flashed.

With the phone back in hand the detective easily unlocked it and, giving the young boy full view of the screen, he texted himself and John a joint message so that they could save the number onto their own phones. The awe and confusion on the boy's face was evident.

"So what? he doesn't know how to work an iPhone. Not everyone grows up privileged, Sherlock," John commented, removing his outside wear in the futile hope that it would encourage Sherlock to do the same rather than walking on a brand new carpet in unclean shoes.

"You're comparing your own childhood exposure to technology, erroneously, to children growing up today. Harry here may have been neglected at best growing up, but he was in a wealthy enough household alongside two parents who spoiled their son rotten with material objects.

"They wouldn't have denied him a phone, and they'd have given him the best that they could buy. I don't doubt Harry has never held a mobile phone in his life by the way he handled this one, but to have never seen someone else even turn one on? Not in TV shows, movies, adverts, online videos, or real life?

"After all, his attendance may have been unreliable, but he did go to school with other children his age and I'm certain childhood hasn't changed that much that little boys and girls have suddenly become disinclined to boast to their peers," Sherlock rattled off his observations with speed, staring intently at an increasingly uncomfortable looking Harry all the while.

"Just because he's seen them before doesn't mean he'd know how to work one, he's not like you who could probably tell how to work one within moments of seeing it in someone else's hand."

"No of course not, but it begs the question of why it didn't even occur to Harry to touch the screen."

Which.. well that did occur to John as a bit odd but then he didn't know what kids did and didn't pick up these days without being directly taught, and he figured there was a reasonable explanation to it all, even if -knowing what he did so far of Harry's childhood -it was an unpleasant one.

"What do you suggest it means?"

Sherlock waved a dismissive hand in both John and Harry's direction, "I don't have enough data yet. It's a capital mistake to theorise before I have proper data."

John cleared his throat and glanced awkwardly down at the silent child, "right, that's fine and all but you have weeks to gather data and Harry's just standing around with nothing to do," he turned fully to the solemn faced boy, "Why don't you take your shoes, coat and scarf off and place them over- oh look we have a shoe rack now- over there. Afterward I'll show you around and see if we can find where Mycroft's placed the rest of your new things."

"I'll have some tea while you're at it," Sherlock absently demanded from where he was once more inspecting the flat for bugs.

John rolled his eyes, "tea, Harry?"

"Uh, sure. Please."

Once they were both stripped of shoes and coats John gestured for the child to follow him, "I'll show you the kitchen and bathroom while I'm making his majesty a cuppa."

He led the boy into the kitchen only to be faced with a glaringly obvious change.

"Sherlock!" He called, "What am I looking at?"

"It's a mini fridge freezer, John," Sherlock's muffled voice responded.

"Yes I deduced that for myself, thanks, but what's it here for?"

"It's for my experiments, and it has a magnetic lock on it so that childish hands can't ruin anything."

"Why do I feel like I'm the one being insulted," John muttered. It was a good idea though, and hopefully it meant no more instances of John opening the fridge only to find body parts contaminating the food.

He turned back to Harry, who was systematically opening cupboards and drawers and peeking inside them, one by one.

"Like Sherlock just said, Harry, the little fridge freezer is for Sherlock's experiments so there shouldn't be any in the bigger one. Help yourself to anything you find in there as long as it's in date. But if you do find anything that...shouldn't be in there it's best not to eat anything and tell me," he gave a brief smile at the boy, who nodded in reply.

"Who does the cooking?"

Ah, John thought to himself, home cooked meals are supposed to be a thing now. Takeaway almost every mealtime wasn't really an option anymore.

"Mrs... Hudson?" He guessed uncertainly to himself, already feeling a little guilty for the unconscious assumption he realised he'd made that Mrs Hudson would be happy to take the bulk of Harry's meals on.

"You'll be able to get three days worth of meals a week from her, and a fourth dinner if Harry personally claims to be hungry on the day," Sherlock called, "of course I predict around a sixty percent decrease of tea and biscuits and an eighty percent decrease of cleaning from her as a result."

That succinct summarisation of just how much they could take advantage of Mrs Hudson's generosity really didn't do anything to assuage John's guilt.

"I can cook," Harry offered. John remembered the scars Sherlock claimed were from being forced to cook at too young an age on Harry's arms and made a face.

"Perfect. Problem solved," his socially oblivious flatmate responded, sweeping past them in the kitchen and opening each drawer until he found a rolling pin.

"No, not perfect. We can't make him cook like his relatives did," John protested, raising his voice to be heard over Sherlock gleefully smashing little bits of technology that were clearly Mycroft's bugs with the rolling pin.

"Don't be an idiot, John, we're not making him do anything, he offered."

"I don't mind," the boy assured, "as long as I can cook what I want to. I know quite a few recipes."

"There, see? And if I know Mycroft..." Sherlock walked over to their original fridge freezer and pulled it open revealing it full of ingredients that hadn't been there that morning. Sherlock scanned the contents and grimaced in irritation, "he knows I don't like beetroot."

After a hesitant pause the doctor heaved a reluctant sigh, "fine, but Sherlock and I are perfectly capable of doing the occasional cooking so don't feel like you have to."

"Yes, yes. We won't force you to cook and clean, we won't hit you or keep you under the stairs," Sherlock rolled his eyes.

"How do you know about that," Harry coolly demanded, his eyes narrowing and his body tensing defensively.

"You show minor signs of long term lead poisoning."

"What!?" John burst out in alarm, scanning the young boy but unable to spot whatever it was Sherlock had seen to lead to that conclusion.

"It didn't show up in your blood work because you've been missing from your previous residence for months and possibly due to that 'mystery' compound in your blood caused by the 'mystery snake' and the 'mystery' cure," the detective continued onward, putting sceptical emphasis on 'mystery' and ignoring John.

"What's lead poisoning and what does it have to do with anything?" Harry questioned, his green eyes still narrowed.

"It's a toxic metal that was used in the pipes and paint for houses before it was banned in 1992. That doesn't mean old houses aren't still equipped with it. You've lived in the same house almost your whole life, correct?"

"Yes," Harry replied uncertainly. John, on the other hand, cared less in that moment about whatever deduction Sherlock had made and more about the fact that he hadn't informed the doctor who would be the most responsible for the child's health.

"As I suspected. You were raised in a house that used lead, but you're only showing minor effects- in the pallor of your skin, where it's worsened your eyesight and your lack of growth, but most tellingly in the lining of your gums. Your relatives wouldn't have given you filtered water if they even had it, so theoretically you should be experiencing the same or worse symptoms than them. I've seen their pictures however and that theory doesn't hold up to the evidence.

"The other explanation is that the house had rooms painted with lead paint that you spent next to no time in. But as I've already stated, they were wealthy enough and they would have made sure each room was decorated to their standard even if they wouldn't spend any money on making whatever room you stayed in comfortable.

"This suggests you either had an attic or basement for a room. But then I noticed your X-Ray showed barely visible scarring on your lungs from sawdust you've inhaled consistently over a long period of time. The only wooden place in a house disturbed constantly enough to produce a consistent dust is the stairs. If you could fit under the stairs for an extended period of time, leaving the larger storage spaces free for their original purpose, why wouldn't people who prioritised keeping your existence as minimal to them as possible when you weren't making yourself useful keep you under the stairs? Thus, lead poisoning from the pipes, but less than your relatives who had much more exposure to the paint."

Harry stared at Sherlock with wide eyes, looking simultaneously impressed and chagrined, "yeah that sounds about right. So I've been... poisoned?"

"Not severely. The lead is no longer in your blood, or you would have been treated for it at the hospital. Over time your appetite should improve, you'll come to feel more energised, less irritable and you'll put more weight on."

"Harry why don't you check out the bathroom, it's through that door and just to the left," John levelly suggested as he glared at his flatmate.

The perceptive boy glanced between them before he gave a quick nod and left the kitchen.

"Why didn't you tell me he's had lead poisoning?!" He hissed furiously, trying to keep his voice down so Harry wouldn't hear.

Sherlock gave him a bewildered look, "I did."

"When?" He snapped disbelievingly.

"Just now. I know you're mentally slow compared to me, but this is a little extreme don't you think?"

The doctor breathed in angrily, ready to let rip on his best friend's blasé response to the health of a child that they were responsible for, when his brain translated what his socially incompetent flatmate meant.

"You only figured it out just now, you mean?" He clarified, and received his answer in the childishly petulant look Sherlock wore in response.

"Very few people on the planet could have come to that conclusion quicker than me," Sherlock responded in defence, mistaking John's question for an attack on his intelligence.

"Sherlock, I'm not... it's fine, I thought you were- never mind. Let's just get the tour over with. I'm tired and I have work at the clinic in the morning," John rubbed a weary hand over his face, suddenly feeling the long day like a physical weight now that he had admitted to his exhaustion.

Proving that their conversation had been less than private, Harry quietly reappeared the moment John spoke those words, and a part of John realised that living with a child soldier was probably going to mean a fair bit of paranoia from the kid.

"Which toothbrush is mine?"

"The one that isn't blue or white. That door past the bathroom leads to Sherlock's room. He prefers no one enters barring an emergency, but don't expect the same consideration from him in return, he's a bloody hypocrite-"

"Your room is shared with John," Sherlock butt in.

"Wait, what?" John felt quite indignant that he didn't get a say, although after a second of thought he realised it was also the only obvious option. There was no way Mycroft would have expected Sherlock to share a room gracefully and John had the bigger room.

"You'll probably find a futon or sofa bed in your room, as well as furniture containing his clothes, judging by the sofa in the living room."

"What about the living room sofa?"

Sherlock scoffed, "how you didn't notice that it's sofa bed is beyond me. During nights that I intend to sleep through until morning Harry can use it. He'll have your room to himself half the time anyway due to the on and off again girlfriend you think you've been keeping a secret."

"Right. I'm too tired to deal with this," John commented dully. Judging by the fact that Sherlock still hadn't taken off his coat or shoes the Doctor doubted that his flatmate would be sleeping any time soon, "come on then Harry, let me show you upstairs where my room is."

Everyone had eaten before Harry was picked up at the hospital, so he didn't feel obliged to do anything else that day besides get into his pyjamas, sleep for at least eight hours and try again in the morning.

Hopefully a full day alone with Sherlock would open Harry up enough that he'd feel more comfortable talking, considering the boy's obvious withdrawn attitude from the moment they'd gotten in the taxi. He was clearly capable of standing up for himself and if nothing else spending an extended time with Sherlock was bound to aggravate anyone enough that they crumpled like wet paper or were pushed into asserting themselves.

He felt like there was something he was forgetting to tell the detective, but he brushed the thought aside and led Harry onto the landing so they could go to his room and find some night wear for the boy.

"John, you forgot to make me tea," his arsehole of a flatmate called after him.

"Oh, piss off and make it yourself," he grumbled, certain that he could hear quiet laughter behind him from both the detective and his mini lookalike.

How do you think Sherlock and Harry will fare alone together? What do you think going to school will be like for Harry?

In terms of the timeline of both Harry Potter and Sherlock combined that's part of the mystery.

Just know Sherlock returns sometime between October and November 2013 and season 3 kicks off early Nov 2013. I've pushed the timeline around so that Sherlock returned on the same date, but it's now the beginning of Jan 2014- time for John to forgive Sherlock without the threat of a bomb- and season 3 has yet to kick off.

Next time: Mrs Hudson meets the new addition to 221b, Sherlock avoids being bored and Harry gets some closure at Barts Hospital