Notes: Okay, this fic has been sitting on my hard drive for years now, so I might as well publish it before it dies of old age.

Fixing their post-case cup of tea had become something of a tradition to John by now. He made it extra-strong and extra-sugary to celebrate the fact they had once more avoided dying a most gruesome and ridiculous death. In a slowly filling vat of liquid chocolate of all things, this time around. Now that he thought about it, maybe Sherlock's theory about all candy-makers being evil had some truth to it. Speaking of the devil, he was yelling something unintelligible from the living-room, which meant he was making an effort to be heard instead of just nattering on as if John was right next to him as he so often did. He had actually gone through the effort of checking his whereabouts first. Progress!

"How long have we had a new tenant in the flat across the street?" Sherlock repeated more loudly this time. He had to think it was important, which didn't mean it was as he had his own peculiar idea about what was and wasn't important.

"Do we?" John replied while he rummaged around the cupboards for biscuits.

Chocolate hobnobs would be heaven right now. But he'd make do with plain digestives or even ginger nuts if there was nothing else. He was starving.

"Never mind," Sherlock replied in that tone of voice meant to convey he was an idiot without having to actually say it. "Sometimes, your lack of observational skills astounds me, John. Do you think there's something wrong with your brain? I know it's not your eyes, your aim is too good, so it has to be your brain."

John rolled said eyes as he walked out the kitchen and set the platter down on the small rickety table sitting between their armchairs with more force than was strictly necessary, ignoring the resulting tea-spillage. The table was already so stained, it might actually improve it by making the discolorations more uniform. John glanced at his flatmate, about to call him over, but Sherlock was gazing intently through the window, piquing his curiosity. It was already dark out, so John wondered how he could actually see anything other than his own reflection in the glass pane.

"Fetch me the sugar bowl, John," Sherlock demanded, his eyes still riveted on something across the street.

John looked over Sherlock's shoulder but couldn't see anything amiss, then back at the cup of tea he'd prepared for him with its fragrant tendrils of vapour still curling upwards and he frowned.

"Why? What's wrong with your tea? As a doctor, I feel obliged to tell you three sugars is already stretching it."

That would be surprising. For as long as he'd known him, Sherlock took his post case tea with two sugars and he was a creature of habit when he didn't put everything on hold for a case. Then, he became the most unpredictable man on Earth.

"Don't be daft, John. The sugar is not for me."

The "obviously" was heavily implied, causing John to sigh. He gave up on trying to follow Sherlock's line of thought tonight, lest the furrow in his brow dig a permanent groove there. Sherlock was definitely in one of his 'moods' where he wasn't inclined to explain himself, leaving John no choice but to watch the events unfold in a constant state of befuddlement, and cross his fingers in the vain hope Sherlock didn't get himself in trouble again. He hated when Sherlock was in that mood. It made him feel twice as stupid as he usually did next to his genius of a friend.

Reluctantly, John snatched the sugar bowl from where he had left it on the kitchen counter and returned to the sitting room. Sherlock had not moved an inch, his intense gaze still lingering on a point across the street.

"Here," John said, thrusting the bowl in his direction, the china lid tinkling in protest at the rough treatment.

Sherlock plucked the delicate lid off between two fingers and upended the bowl, the sugar piling at their feet in a perfect, little white cone. John began to ask what the buggering hell that was all about, horrified at the waste of perfectly good sugar, but cut himself off as soon as the first syllable was out of his mouth, because he was right: Sherlock was in one of his moods and John would just be wasting his breath trying to weasel an explanation out of him.

"Sadly, we ran out of sugar. I'll go ask the neighbours if they can spare some," Sherlock stated in a monotone and left before John could point out they had plenty more in the kitchen, and even if they didn't, Mrs Hudson certainly would.

But Sherlock obviously wanted to annoy the neighbours tonight. Better them than me, John thought, delighted at the fact that he could finally crash in his armchair to drink his tea in peace while it was still hot. His only worry now was that they had no other neighbours in 221 besides Mrs Hudson and Sherlock never needed an excuse to go visit her so that's not where he was headed. The basement flat, 221C, remained woefully empty as far as he knew because of the damp, and Sherlock was not so far gone into crazyland that he would ask the mold growing there to borrow some sugar. Besides, judging by Sherlock's disconcerting fascination with whatever dwelt opposite their flat, that's probably where he was headed. It was going a bit far for a little sugar they didn't need, but not if he wanted to go snooping around. John wondered if he would hear the annoyed shouts the detective was bound to provoke from all the way across the street. It was, sadly, a very likely probability. That or sirens. It wouldn't be the first time someone called the cops on him, and half the Yard would just love to get the chance to cuff Sherlock and parade him around like a prized poodle.

However, Sherlock came back barely ten minutes later with a dazed look on his face and his gait a mere shuffle when he had been prancing out the door just minutes prior. Something was definitely wrong.

"Are you feeling alright, Sherlock? You look...strange."

"I… Yes. No… I'm not sure," he answered, which worried John so much he jumped out of his chair to check on his friend, spilling tea for the second time that evening.

Sherlock looked just as he had on his way out, but when had Sherlock ever not been sure of something before? He either knew, or he didn't, and he wasn't shy about admitting either, but this uncertainty… that didn't bode well, his mind simply didn't function that way.

"Did you hit your head on your way out?" John asked, guiding Sherlock with a gentle hand to his own chair and pushing him down in it, his fingers beginning to comb through his curls in search of a bump.

"I was out?"

"Alright, that does it. Take your coat, I'm taking you to the hospital."

He must have hit his head. It was the only explanation for his apparent loss of immediate memory and his dazed look.

"No, I'm fine. I mean… I'm not hurt. I'm just... confused," Sherlock replied with more confidence then eased himself in his chair in a clear refusal to be moved elsewhere. "My mind feels like your scrambled eggs."

"Yes, I can see that," John huffed, ignoring the slight to his scrambled eggs which did look disgusting, but actually tasted really good if a certain someone only bothered to try. "Let me at least give you a quick check-up, alright? I'll fetch my bag."

John didn't wait for an answer and ran up the steps two at a time to his bedroom where he had a fully stocked medical bag in his closet in case of emergencies such as these. Living with Sherlock was hazardous even when he hadn't gotten it in his mind to test exotic poisons, unstable acids, or, on one memorable occasion, the pliability of metals.

John kneeled in front of Sherlock and noticed for the first time he was still clutching the sugar bowl in a death grip. He had to literally pry his fingers off one by one. Once freed, John realized from its weight it was now filled and a quick check reassured him it was indeed filled with sugar and not say, a very small snake or very big spider. Or explosives. But no… just plain old sugar. He was almost disappointed. Setting the bowl aside for the time being, John began his usual routine on Sherlock: checking his eyes, paying attention to his skull in particular, asking questions, testing his reflexes and even his blood pressure but everything was completely normal. There wasn't the slightest bruise or tender spot to be found on Sherlock's entire thick skull and John had been thorough in making sure of that, despite the mass of curls making it a long and laborious task. As far as John could tell, Sherlock was in perfect health. He even seemed to be enjoying what was basically a scalp massage, the prat.

"I really think you should go to the hospital, pass a scan, just in case I missed something," John said, biting his bottom lip.

"Why? Because you can't find anything wrong with me?" Sherlock teased then snorted in derision. "No. I trust your skills as a doctor and I have a mystery to solve. No time for hospitals. Hospitals are boring. Except the morgues."

"And which mystery would that be?" John asked, already knowing the answer.

"The case of the self-filling sugar-bowl, of course."

"That's a really lame name, you know."

"Well, you're the writer. What do you propose we call it?"

"I can't know that until we've solved the mystery, Sherlock. That's the whole point. And there is no mystery. You went out to fill the sugar bowl, the very one you purposefully emptied on the floor, might I add, and came back with the sugar-bowl filled. You're just dizzy because you sprained your brain trying to be polite to the neighbour or bumped your head on the way back. It's your own fault for being so freakishly tall."

John put his instruments away and sat back down, scowling when his next sip of tea proved cold. Damnit. Every time.

"First of all, I do not bump into things by accident. Ever. I'm not some awkward, blundering oaf. Second, you should blame my parents for my height, or yours for your lack thereof. No need to be so jealous."

"I'm not… never mind," John said and took a deep breath while the mantra pick your battles, pick your battles played on a loop in the back of his mind. "So what happened, then? Someone attacked you when you went out to get some sugar, but you saved the bowl without spilling a single grain of its contents?"

"I can't tell you how possible that eventuality might be until you give me a precise account of what happened, John. You know that."

John huffed in irritation as he realized he had just been retrograded to simple eye-witness.

"Oh, alright! You went out-"

"No," Sherlock cut him off, giving him a sharp look.

At least he was back to his old self. No sign of any lingering dizziness whatsoever. That ruled out drugs too, which was a relief and the only remaining reason he'd wanted to drag Sherlock out to A&E.

"What do you mean 'No.'?"

"Before that? What was I doing before going out? What did I do? What did I say?"

"Uhm...You were staring out the window there," John started, indicating the living room window where Sherlock usually played his violin. "You asked for the sugar bowl, tipped its contents on the floor -it's still there, by the way, and I'm not cleaning it up - then you left saying we ran out and were going to ask the neighbours."

"That's strange," Sherlock commented.

"You're telling me," John muttered, but not low enough as it clearly amused his so-called friend. "Oh, wait. Before that, while I was fixing tea in the kitchen, you asked me since when we had a new neighbour in the flat across the street from ours."

Their gazes met and they hurried to the window, inspecting said flat. John had been right, it was hard to see anything except their own reflections, especially because the place they wanted to inspect was plunged in darkness.

"Lights," Sherlock ordered and John jumped to do just that, telling himself it was out of habit and not because he enjoyed being at Sherlock's beck and call like some Yarders had so snidely commented.

"Looks like it's empty," John said.

"You mean the tenant is not currently at home, because the flat is definitely lived in. See those plant-pots on the window-ledge, a bit of a safety hazard if you ask me. And there are drapes hung on all the windows. A shame we can't see anything more in this darkness though."

"Stakeout, then?" John asked.

"Definitely."

They had pulled their armchairs to the window and despite the large pot of coffee he'd prepared to replace his cold tea, John must have fallen asleep pretty early in their surveillance of the mystery neighbour. Sherlock, of course, hadn't.

"Anything new?" John mumbled when he woke up to the greyish dawn light, then yawned and stretched his stiff limbs.

"Our mystery neighbour has not returned yet, but I can tell you it's a woman and she has a cat, but no boyfriend. She likes to read and knit, but has a strong dislike of technology."

"Sounds like an old spinster to me," John deduced.

"One would think so, yes, but look at the couch."

John did so and spotted a red, glittering gown discarded over it. The kind of dress women wore at galas if their tits still pointed North. A young woman, then. Probably attractive if she managed to pull off wearing such a dress. John grinned, his mind having wandered to its more salacious recesses.

"What's with the smile, John. I never figured you to be such a lecherous old man."

"What- No!" he sputtered indignantly, feeling his face grow hot because Sherlock was, as usual, spot on. "Actually, I was thinking of a possible scenario that would explain this mystery."

"Go on, then," Sherlock said, clearly not believing him.

"You knocked on her door to borrow some sugar and were so love-struck by her that it addled your mind."

"Ridiculous," the detective scoffed.

"I know, but it's funny to imagine," John paused. "Have you ever been in love, Sherlock?"

"Whatever for?" his friend asked as if he had just been insulted or asked if he'd ever eaten a worm.

John hummed in understanding.

"Yes, I thought you might say that."

"It still doesn't explain why I went there in the first place. There's nothing suspicious that I can see."

"Maybe you know her. The woman, I mean. Maybe you recognized her and went over there to investigate."

Sherlock, for one, didn't dismiss his idea outright and even gave it a few minutes consideration, but ultimately, he didn't look convinced. He had no better explanation to offer himself though, and they returned to their vigil.

When the evening darkened the sky once more, the lights in the flat opposite flared to life and the two men sat on the edges of their seat, their noses almost touching the glass pane. Sherlock had been right again: their neighbour was a young woman. She crossed the wooden floorboards and threw a dark cloak on the couch along with a small beaded purse, then kicked off her shoes and flung herself on the battered piece of furniture.

"Messy," Sherlock commented.

"You're one to talk. I found an eyeball you left behind in the microwave this morning. I thought it was an old raisin at first. And we've been using that microwave to heat our food, Sherlock." John's eyes strayed to the white cone of sugar nearby. "And you still haven't cleaned up your sugar pyramid!"

Sherlock grunted in disinterest at such domestic trivia. They silently observed the woman, but she wasn't ringing any alarm bells as far as John was concerned. She looked to be in her late twenties and had the longest braid of hair John had ever seen, tufts of it apparently trying to escape its confines. Pretty, in a subdued sort of way, that contrasted wildly with the red gown glittering next to her under the artificial light. An orange blur suddenly pounced on her and she laughed, petting the squash-faced animal. It was the ugliest cat he'd ever seen but she seemed to like it, until she abruptly stopped her petting and stared straight at them, her brows knitting down in a furious scowl.

"Busted," Sherlock said, not at all abashed, like a kid who had skipped school and had fully expected to be caught. The berk even waved at her.

John's reaction was a bit more extreme: he lunged out of his chair, hiding under the window-sill, mortified he had been caught spying on a woman in the privacy of her home. Damn Sherlock, it did make him feel like a lecherous old bastard. Sherlock, in direct opposition to John's movement, got up and straightened his rumpled clothes.

"So, shall we go introduce ourselves?"

"Are you mental? She's going to call the cops, you git!"

"I highly doubt it," Sherlock said. "Besides, she closed her curtains, so we can't spy on her anymore and I need more data."

John picked himself off the floor, annoyed Sherlock had not told him he could stop hiding sooner. He was probably laughing inside, the git.

"That only proves she does not wish to see us, or for us to see her. Just leave it be, Sherlock. She looks harmless enough. Admit you simply bumped your head on the way back and be done with it."

Sherlock smiled.

"You know me better than that, John. Come on, it'll be fun."

Generally, Sherlock's idea of fun was not his own, but John followed him across the street, if only so he didn't get another dizzy spell on his way back. They scanned the list of tenants at the front door.

"There," John said, pointing at the newest looking tag that just read H.G.

"Very good, John. What else can you tell from it."

John thought for a minute, rubbing the stubble on his chin and making a mental note to shave when he returned home.

"Neat lettering, old fashioned, hand written. Not typed out on a computer like the others, but you already said she disliked technology. It's very strange she only wrote her initials instead of her name though. I've never seen that done before."

"And?"

John shrugged, not in the mood for Sherlock's little games. He knew the detective would fill him in on whatever it was he'd missed.

"Using only her initials suggests she neither wants nor expects company, but also that she doesn't expect any post or deliveries, which is highly irregular. And most people procrastinate for a long time before putting their name on the outside doorbell after they just moved in. She's efficient, organized. Her writing suggests the same: it's very neat, as you pointed out, and sharp, without any of the frills women usually favor."

"But you said she's messy, earlier."

"Yes, where it doesn't count. Clothing for example, or housekeeping. It's a reasonable distinction to make."

"So she's a bit like you," John pointed out, still miffed by the sugary mess that hadn't been cleared from the floor in the middle of their living room.

Sherlock ignored him and rang one of the other bells to have a neighbor open the door for them. They made their way up the stairs, John wondering all the while why he was letting his madman of a friend go through with his idiotic plan. He wasn't encouraging him, but he wasn't stopping him either. Sherlock knocked on the door, and a minute later, they could hear a bolt being pulled back. And then another, and another… Four in total. Sherlock raised his eyebrows, clearly surprised, which wasn't something John witnessed all that often. The woman stood there, the door only half-opened and probably ready to be slammed shut in their faces. The scowl on her own pale face made her appear older than John had previously thought.

"I hoped you wouldn't be coming," she said by way of greeting.

"Sorry to disappoint," Sherlock answered, not sounding sorry at all or even perturbed by such a cold welcome. John, on the other hand, was having seconds thoughts and inched closer to the stairs.

"Could I borrow some sugar? I seem to have ran out," Sherlock asked in a sweet voice that set John's teeth on edge.

John would never get used to Sherlock's ability to lie so easily. The woman's frown was losing a battle with the spasmodic twitch of her lips though, and a shadow of a smile ultimately won.

"Ran out again?" she asked.

So she was the one who gave Sherlock the sugar.

John looked at the detective but his face was as unreadable as ever after he'd dropped the fake sweetness.

"Oh, no. I have plenty on the floor, but I've been told not to eat what I find there. Something to do with health hazard, I believe," Sherlock replied, which did catch the woman off guard.

She looked about to ask why his sugar was on the floor or why he'd need to be reminded not to eat anything found there, thought better of it and just shook her head. She looked over at Sherlock and then him. She had brown eyes much like Greg's, that could be as cold as chips of coal or as warm as hot chocolate depending on who they were directed at. John hoped very much this wasn't the DI's kid sister or something, or the man would skin them alive.

"And where's you sugar bowl?" she asked.

"Oh, seems like we forgot it, silly us. You might as well invite us in for tea. It'll save us some back and forths."

Oh, come on! She's bound to slam the door in our faces now, John thought, bracing himself for it. But to his surprise, the woman sighed, opened the door wider and motioned them in.

"I'm Hermione Granger, by the way," she said, shaking Sherlock's proffered hand. "But maybe you already knew that from spying on me."

"Sherlock Holmes," his friend said, unperturbed at the jab. "And this here is my friend, Doctor John Watson."

"Oh, that's nice," she said with a sweet smile, looking speculatively from Sherlock, to him and back again. John hated that look, he'd seen it much too often.

"Not like that," John muttered, knowing exactly what she was thinking when Sherlock had introduced him as his 'friend'. Maybe it was the way he said it. "I swear, every time..."