Disclaimer: I do not own Sherlock Holmes, Doctor John Watson or Sirius Black - most if not all characters and terms belong to either Miss JK Rowling or Sir Arthur Conan Doyle. However plot and any new characters belong to myself. (Sure, if I owned any Harry Potter/Sherlock characters I wouldn't be writing fanfiction, I'd be rolling around in vast piles of money.)

A/N: Hey, fancy seeing you here. This is my new fanfiction, funnily enough. I've been toying with the idea of a Potterlock fic for quite some time, but I've never really gotten a proper idea until now. I do hope you like it - reviews and advice and all that is hugely appreciated, it'd make my day.
Au revoir,
scribbled thoughts

I heard him enter before I saw him. The door gave a mewling creak as it swung open, followed by faint steps. His footfall was always so soft, so careful. The gait of a man unsure of himself. At the time, I was unoccupied. I hardly classify writing a letter to one of my dearest relatives as anything worth mentioning in detail.
Quill tucked behind my ear, I looked into a face sprinkled with scars and freckles.
"Moony?"
My voice echoed in the barely-furnished room, empty but for a table, chair and two figures.
"There's been another attack." Remus informed me,"Death Eaters, obviously, in Muggle London. It's suspected that at least two of the bodies are our kind."
At least two… Meaning that not one, nor two, but several people were killed off like vermin in a display of power and cruelty. I inclined my head in a short nod, brow knitted together in a frown. This was not the first completely unprovoked Death Eater attack, and it would not be the last.
"So it's just the usual, yeah?" The usual procedure. Remove traces of any of any magical evidence, Obliviate witnesses, stop the murder from flooding the papers. Keep it under control, because anything else would risk letting the cat out of the bag. Albus Dumbledore didn'tlike risks, saw them as stupid and reckless.
"Yes, yes…" Remus confirmed hurriedly, grabbing my leather jacket from the hook in the hallway and throwing it at me.
"Hurry up, Padfoot, time is ticking."
I waved him off with one hand, grunting slightly as the jacket landed on my head. My letter lay in front of me, unfinished, and I scribbled my signature in loopy scrawl before tying it to the leg of my owl. The ball of dark feathers squawked and shook its leg fiercely, as though to protest being used as a messenger. With a nip at my hand it plunged off the windowsill and disappeared into the evening.

Slipping into my jacket and discarding my quill on the table, I began to make my way downstairs alongside Remus.
"So is it just us, or…?" I trailed off, crooking one eyebrow.
"Just us." Was his reply, "Peter apparently has the flu."
"Bullshit." I scoffed, "He's just too lazy to get off his arse for once. He uses that excuse for practically everything… He seems to forget that we know him better than he knows himself."
Remus simply shrugged,
"Either way, he's not coming along. Frankly, I don't even want to think of what Prongs and Lily are up to…" He shuddered. "Dorcas, Mary and Emmeline are on a mission elsewhere, Frank's gone to Ireland to visit relatives, Arthur works late on Thursdays… And I haven't heard from anyone else."
I nodded, only really half-listening and absent-mindedly running a hand down the oaken banister of the stairs. When my palm left it again it was coated in a thick layer of dust and grime, and I crinkled my nose slightly in disgust. We had a house elf, Kreacher, but he despised me and had given up trying to make the house look reasonable since the day my mother died. Since then, I'd been left alone in Grimmauld Place. To be perfectly honest I'm not always completely by myself – once in a while Marlene stays over and takes a guest room if she's too drunk to face her parents. Also, Remus has been a regular visitor for some time. He's had difficulty with finding work and a place to stay considering his… Condition… And thus seeks me out for a few nights at a time. He was pretty much the only person I saw excessive amounts of, now. Everyone else had their own perfect little lives to attend to. Whether they still lived at home, like Dorcas, or they'd found a house of their own, like Lily and James…
I'd eagerly offered up Grimmauld Place as the meeting place and headquarters of the Order of the Phoenix. At least now the sitting room would be filled with friends talking, once a month or so, whether it be exchanging pleasantries or discussing tactics.

As soon as I stepped foot outside the house, Remus rested his hand on my shoulder and we were yanked into the whirlwind of Apparition. I was satisfactory at Apparating, but considering I still had no idea where we were headed – apart from the vague description of 'Muggle London' I was given – and the fact that Moony was useless at describing places and giving directions, it was much easier to simply perform side-along Apparition.

When the world finally stopped reeling, I found myself standing in one of many dark alleyways. I felt Remus' hand slip away and we walked out of the back-street, towards the scene of the crime… We were not alone.
Two figures stood over half a dozen bodies – men, I assumed, from their stance and figures. From afar the details were unclear, but as we drew nearer it was obvious that one towered over the other in height. The taller turned to us, sharp eyes flicking over my face, my features, as though to capture a photograph and tuck away the memory in files deep within his mind.
Shorty hadn't quite noticed us yet – he was stooped beside one of the victims, gaze skimming for injuries, any sort of evidence as to why the deaths had occurred.
I knew he wouldn't find anything. With only a single glance at the six people, I could tell by their agonised expressions that the Death Eaters had toyed with them for a while before killing them off with the most dreaded Unforgivable curse…
Tearing my eyes away from the two men, I slid my focus onto my surroundings. I took it in – the crime scene, the police car parked nearby with a faulty tail light, the policeman striding towards us at an alarming pace. I hoped he wouldn't give himself a heart attack; he seemed rather red in the face already. A voice in the back of my mind faintly wondered that the guard was not a fan of personal hygiene, with his collar dirtied and a splatter of something marmalade-esque on the pale material.

"Excuse me, gentlemen, but I'll have to ask you to move along. This area is not… Open to the public."
The policeman ordered in a gruff, slightly breathless tone. Remus opened his mouth to make some kind of excuse, but I suppose I'll never know what he was going to say as there came a shout from another policeman a few metres away.
"Leave 'em, Tommy, they're with me!" He called over, and I flashed him a grin. Carl Davies, one of us, one of the Order. It was useful to have members of the Wizarding World stationed in various Muggle jobs – it was the key to getting pretty much everywhere and anywhere.
Tommy tipped his hat at us in apology and backed off, gesturing for us to step under the oval of police tape. We did so, and my gaze connected with Taller-one once more.

"Sorry, who are you?" I questioned, barely finishing my sentence before he cut across me.
"Sherlock Holmes, consulting detective. And my associate – Doctor John Watson." He replied in a clipped air. Shorty glanced up at the sound of his name, before straightening up and shaking both our hands.
"Sirius Black and Remus Lupin." I added, though Holmes didn't seem particularly interested. He had turned back to the point of our presence, and was muttering softly under his breath, too faint to figure out what he was saying.

"Peculiar names." Sherlock suddenly said, without turning to face us.
"Sirius… Lupin… Not the most common names for Englishmen."
"Pot calling the kettle black." I retorted, "You don't hear of many Sherlocks strolling around the country, eh?"
The man simply shrugged at me, swiftly changing the topic.
"Six civilians are found dead in the middle of London. Three unemployed, one waitress, one nurse and a college student. They all went through obvious trauma leading to their deaths, but there are no physical wounds anywhere on their bodies as far as I can see… The question is not why, but how? Who?" He breezed through his brief analysis, and it struck me that he had not been planning those words for a long time, but that he was speaking as the thoughts came to him.
"Sorry, but just how did you come to realise their occupations?" Remus queried, sceptical.

Sherlock sighed a heavy sigh,

"The nurse. Her hair is down, but a slight crink is present in it near the skull, suggesting that she is either performing intense work and requiring it out of her face, or that she needs cleanliness within her everyday routine. Undeveloped muscles and short stature confirm the latter. She reeks of hand sanitiser and iodine, which is present in most cleaning solutions used in hospitals. Obviously a nurse.
The waitress. A low-paid job, judging by a stained shirt and re-hemmed skirt. On the shirt cuffs, again the stains. Food stains, most probably from cleaning off tables. Maybe she's just fond of food? Unlikely. The stains on her clothes smell high in sugar and a lancing device in her pocket informs us of diabetes. Thus, the food cannot possibly be hers, as her condition and foodstuffs high in sugar content tend not to mix well. What about being a chef, you might ask? Ink smudges on her hands tell us that she regularly takes notes. Food, writing, low-pay, waitress.
Then the college student. Again, plenty of pen-marks on his hands from the taking of notes during lectures, and what can only be a paper cut on his left forefinger, most likely from turning pages too quickly. Reading glasses in his jacket pocket, everything indicates to something in which he reads and writes. A teacher, perhaps? Not a chance. Too young, says his ID and teeth, too young to have a teaching degree. Must be a student.
Which leaves us to our three unemployed. Two were obvious, one took slight guesswork. These two here are obviously living off the Dole, they have slim figures and cheap, mostly-polyester clothes that suggest they don't have much money available to them.
The last one, here, was also unemployed. Few wrinkles or stress lines indicating they are not under the sort of pressure a job creates – and of course she is not wearing makeup, her facial skin is not powdery or greasy or any different to her arms, and her eyes seem strained from staring at a screen all day – aren't TV addicts just lovely? Bitten nails and terrible cuticles suggest poor hygiene, because clearly she has nobody to impress, no boss, no co-workers, no partner either."

Silence.
Remus blinked at the detective, speechless. I, on the other hand, rarely found myself at a loss for words.
"Brilliant." I breathed, at the same moment Watson gushed the same compliment. Sherlock offered no particular recognition of the comments, but that didn't surprise me; he didn't strike me as someone who valued the opinions of others much.
The silence that fell between us was quickly broken by Moony.
"Seven o'clock… I have to go, Sirius, can you finish up here? I trust you." He gave me a stern look as though to remind me of my duties, and I simply laughed softly and winked back, watching as he hurried off to Merlin knows where. When his retreating figure disappeared around the corner, I turned to face Watson and Holmes. The latter was staring off into the distance, lips forming words but no sound emitting. He was fascinating to watch, to take note of, to notice his habits and mannerisms. Just by looking at him one could almost see the gears turning in his brain to formulate thoughts and ideas. And his outburst, his speech on the victims… That was stunning, how he'd noticed every little fact and pieced them together to form an answer. It would be such a shame to wipe his memory and keep him from doing what he obviously does best…

Surely, what harm could it be? There was no chance of Sherlock suspecting magic, he was much too logical a man for such 'nonsense'. Albus was being too paranoid, as always.

Reassured that I was not doing anything particularly bad, I bade the men goodbye, wished them luck with their case and sauntered away, rounding into a back alley before Apparating back to Grimmauld Place.
After all, once Sherlock realised that the case was unsolvable, once he'd had his fun, he'd just move on…
Right?