(A small bit of sillyness that wouldn't leave my mind until I wrote it down. Sherlock/Being Human crossover - set mid season one of Being Human (uk) & before the start of Sherlock season one. Ever so slight spoilers for season 4 of Being Human)
He ignores the first letter he receives, elegantly penned instructions in Mycroft's hand, sealed with the twisting insignia of the Old Ones and signed in blood (how delightfully archaic). The second and third are paid even less attention – he's not interested in another boring youngster attempting to 'live clean', it's nothing new or interesting and it always ends in failure and a magnificent mess to clean up after. The forth lies ignored on his mantlepiece for weeks, gathering a layer of dust and experiment residue until Sherlock returns home after another achingly too boring case to the lingering scent of Mycroft and the letter pinned dramatically onto his front door.
There's a folder waiting on the kitchen counter for him and a quick dispassionate glance through its contents makes him pause, flip through the pages again with a bit more interest this time. It's different enough to spark interest and kick start his sluggish brain into motion.
"One house. Vampire. Werewolf. Ghost. Do try not to make too much of a mess dear brother."
Well then.
Intellectually he knows there's Vampires out there who crave the human lives and companionship they once left behind, after all their species tendency to gather in groups was a clear indicator that those needs hadn't died when they did. Still, interactions with humans was mostly a social thing, and although rare, cohabiting with a mortal wasn't going to be any huge breaking news these days... but this? This was new.
This was fascinating.
Sherlock's never felt the pull towards companionship himself, he gets enough interaction through his cases, doesn't need someone prying into the corners of his life and taking up his time. A day into watching the easy familiarity between Mitchell and his housemates has part of him questioning his position.
They're not perfect, far from it in fact – Annie is sweet but too naive and understands nothing about what she's become, George is spending too much energy fighting the werewolf and he's loosing himself to it, and Mitchell... Mitchell is weak. Too easily tempted, clinging too tightly to the support of his friends and it won't last. It's a house of cards that's already wobbling.
But for now they're happy despite their faults. Happy to just be together and, even as Sherlock informs Mycroft that they're nothing to be worried about, that it won't last the year, he find's himself jealous of them. Their warmth has worked its way into him somehow and he can't stop craving what they have. Craving companionship.
Not a werewolf, no, and not a ghost either – he's no time for their particular brand of uselessness but...
He finds himself visiting a small bedsit a day later, moves in the same evening and the low thrumming of his new landladies heartbeat lulls him to sleep that night. Her presence both awakes something needy in him and then at the same time soothes it, but before long quick conversations in passing on the stairs and the sounds and scents of her in the room beneath his just isn't enough. He finds himself dropping hints about needing a room-mate around some of his more predictable companions – and when he first catches scent of one Doctor John Watson among the sharp clean of Bart's, something clicks deep within him.