Notes: This is my first Elementary fic, written I guess because I promised myself (and I think a few Tumblr anons) that I would do it. I've only seen the last few episodes once, so I'm sorry if something is off in regards to specific scenes/interactions.

Not britpicked or beta'd, apologies for any mistakes.

WARNINGS: References to drug use, addiction, and big spoilers for episode 12, "M."

Because You Left

Watson will be leaving, and he'll just have to make do after she does.

It will be different, of course, because despite his numerous attempts, he hasn't been truly alone for quite some time: there was the Work for nearly all his life, and then there was Irene for a shorter while, and then the brilliantly white Addiction for longer than it felt (but we don't talk about that time, they'd said, it's dangerous, it's not healthy), and now there is Watson. Perhaps there will be others, another, but if he is honest he knows he can't stand the thought of going back to that loneliness again, falling prey to the awakeworkworkworkfoodworkwor kworksleep that he had somehow satisfied himself with before Her. He feels nauseous just thinking of it, the cycle, and on recollection his mind can't help jumping to the woman who'd broken it, who'd invited him back to her place, insisted he stay for the night, or for a little while longer.

(Their flat at Baker Street had had light grey walls. She'd always wanted to repaint but didn't have the time; neither did he, when it came to it, but he covered the place with crime scene photos and his analysis and suspects' records anyway. And she was left-handed, all the coffee tables sat on the wrong side in beginning months, but he taught himself into ambidexterity for that, claiming it had been for a case, and she saw right through it but didn't bring it up again.)

He aches for London like a mother most days, but returning to England means the Yard, and the same street corners and dealers lingering at the end of the pavement. And on recalling that, there is an unsettling lurch in his stomach, like he's missed a step walking downstairs; but feeling passes before he can blink, and he never tells Watson a thing.

One day when Gregson has nothing to offer, they waste an afternoon in Times Square after Joan suggests getting some fresh air away from the stuffiness clogging up the house that's begun accompanying his growing messes. He making deductions on the personal lives of passerby, Watson shhing and glaring, and occasionally covering her mouth to politely hide a grin after he saves a few people from scams by loudly pointing out fake designer handbags and faulty merchandise that street vendors are trying to sell to tourists. She laughs outright a few times, but he doesn't, though there is a sense of calm that he hasn't felt in a long while, with her. (It's nothing as good as Irene, he tells himself, but then, nothing will be.) Not for the first time, there on that bench with his would-be apprentice in the heart of a brilliantly bright New York City, he considers sitting her down, turning the tables, dragging out all the evidence and saying you like this, too, I know you do, and we should talk about your addiction.

But he doesn't. And Watson never brings it up, the deductions and their strange kinship, so he must be content with this.

He won't be sorry to see the end of the nagging, of course, the drug tests and therapy groups; but a few times like this, like now, he thinks he will miss it all anyway.

Watson is starting to pack her things, and Sherlock does not offer to help.

She doesn't have much (can't have, with how often she comes and goes, whirling into people's homes without warning and rearranging their lives before leaving just as soon) so it's done within an afternoon. When finished, Joan comes downstairs to see what he's been up to, perhaps suspicious of the quiet, and rolls her eyes when she discovers he's commandeered the living room wall to play with ancient darts he'd found in the spare closet upstairs. She opens her mouth, and he knows she wants to lecture him about using safety boards or gloves or at the very least closing the window in case one of the darts flies astray, but she just shakes her head and moves to the kitchen to make coffee as he continues pecking out a perfectly replicated map of the London Underground on the wall.

Sherlock almost feels it again, the dread. He doesn't presume it will be quite so bad with her gone, certainly not as difficult as the last time he grew attached to a remarkable woman who disappeared from his life and home one day; at least there is a warning, this time, or he should say, one he's paying attention to.

So he drops hints, because it's the only logical conclusion – she should stay, they both know it. She'd make a fine detective, investigator, whatever it is they do and don't do together. And she enjoys what he does, even if the gruesome nature of the cases does tend to upset anyone with a working conscience. A bit restricting, that, in his occupation, but Joan Watson is proof that perhaps it's worth having one anyway.

Of course she'll still be interested, in the After. (It feels as though his life, sometimes, is filled with Befores and Afters, categorizing his history into chapters, perhaps ones titled The Woman and The Big House and The Second Try). Addiction doesn't fade with distance or with time, if the true problem isn't addressed; certainly not if it's something inherent, natural. Simple science, he should tell her – sometimes the chemistry just clicks, the physics of the coordination between two people, drawn together by the science of his art. Of course she'll be interested, why wouldn't she be?

Because she has another client, she tells him on a park bench. It's her job, after all. She'll be leaving soon. It's decided.

Is he fine? Of course he's fine. He was fine after Irene. He was fine after the clinic. He'll be fine after Joan.

That evening, one of her suitcases takes up position in the entry hallway, sitting smartly by the door in preparation for her leave.

Sherlock knows what he's doing, always has. He just doesn't bother trying to convince anyone, least of all himself, into believing he always likes it.

Watson is walking out of his life tomorrow, and Sherlock spends the day with M instead.

Penance, she had once called it, and until that moment he had been quite unsure what it was himself – but that fit, really, it did. A sort of tribute to the Woman and those months, the calm before the storm (though he hadn't known it, of course, at the time). All this personal distance between himself and others, his shield between the rest of the commonwealth: a salute, perhaps an apology for putting the Work first? As if he'd gotten the isolation he'd once craved with sacrificing Irene for the puzzle in those last days, enough so to miss the signs in his hunt for a serial killer that she would be the next target. He never did figure out what her death was meant to indicate: a message, a taunt, or perhaps a warning – it didn't matter, not anymore.

He isn't so humble enough to believe he deserves it; no one really deserves it, in his opinion, coming home to such a scene. (He had moved out that very night, up and left and ignored any further communications from his old landlady who tried to tell him how dreadfully sorry she was, how she rather liked the two of them, had once hoped they would make Baker Street their permanent residency.) Walking into your living room, coming home, laying eyes on that ocean of crimson settled on the floor that was just waiting for your horror. Realizing there was no body, nor sign of a struggle, and in that moment knowing automatically, definitively, the worst. Even in all his shortcomings with Irene, with Gregson, with the Addiction, he knows it's not his fault even if it feels like it should be, most days. This doesn't ever comfort him, but it is something to hold on to, at least, the minute he stands in front of the NYPD with his dusty notes and charts and diagrams, telling them exactly who they're looking for.

Not his fault. It's never the true loved ones' faults, no matter how quickly the regret fills the house the moment they step into their parlor and realize what's gone wrong. (And it always does, there's almost always a personal relation to blame. Watson once mentions that's unfair assumption on his part, or paranoia, to judge so quickly. It's just statistics, he says, and doesn't mention the personal experience. In his line of work it mustn't interfere, not anymore.)

He didn't deserve this. No one does.

Except M. Ah, the exception – but no, he revises, M doesn't deserve this at all. M deserves much worse.

Watson is coming, he can tell – along with Gregson and probably Bell, too, and an entire force of NYPD officers, but Moran is telling him everything and Sherlock's brain, for the first time in years, feels like it's slowing, just a bit. There can't be another, not so late in the game, but the story holds true: Moran was incapacitated at the time of Irene's death, Moran has evidence and an alibi, Moran didn't do it.

"Moriarty," he repeats for the third time, wheezing as Sherlock watches his blood drip from his stomach onto the concrete floor. "It wasn't me, mate. I never touched your bird."

Everything Joan Watson has carefully reassembled in the past six weeks is threatening to topple over. Another target is all his brain registers and he imagines the invisible, faceless murderer, chained and tied up like Moran, and revels for a moment in the possibilities. It's overwhelming, the thought – another puzzle, another riddle wrapped in a personal vendetta – it's almost too much to comprehend that this could drag on for ages, for life, if he's not careful. He needs help. He needs stimulants. He needs the Work more desperately than he ever has.

For a brief second, he almost considers considering It again, before mental processing shudders to a complete halt and everything is paused, just for a moment, as Sherlock closes his eyes.

– what got you into trouble in the first place youre lucky papa send you to new york this time not siberia or to grandmamma youre close this time closer than youve ever been you have a real lead this time dont mess this up remember that first week without her you locked yourself in the new flat and didnt eat for three days and barely made it out alive gregson would be disgusted imagine the look on watsons face you dont want to keep her around this badly not like that –

Irene hadn't minded the drugs. She hadn't liked them, but she hadn't minded. He barely remembers the time she first found out; the grey walls were merging, the patterns on the carpet were swimming, and then She was there – suddenly, miraculously helping him off the worn couch and onto their bed. She'd made him tea. She'd read a dog-eared book, something to do with French philosophers, as he came down.

Think of the track marks. Think of all the time wasted in the clinic. Think of all the times Irene didn't say, "I wish you wouldn't."

It's not working. It's not working.

No? Think of your face in the mirror and failing to convince yourself you didn't look exactly like the corpses you investigate. Think of the afternoon you came home to Irene's blood, all ten pints pooling on the floor of your flat, ruining the carpet, staining the floorboards.

The consideration vanishes as though it never were. Sherlock opens his eyes. Barely a second's passed, Moran is still bleeding and swearing and spitting blood, the screwdriver is still somehow clasped in his sweaty, shaking palm.

Carefully, meticulously (the way Watson might, he thinks vaguely to himself), Sherlock unties Moran and tells him exactly, exactly what they're going to do.

When Watson meets him at the police station, Sherlock doesn't say any more than necessary. If Joan suspects what nearly happened to him in the warehouse, she remains gratefully, blessedly silent. She takes the hint, and then she takes a seat. She doesn't hold his hand or help him to lie down or wait for him to come back to earth, back to her, but it doesn't matter; in a way, she's been doing it all since the moment they first met. It means the same to him, when it gets down to it.

Amazing, she'd said. She'd called his work amazing.

You could be a part of it, he didn't say. You want to. You should. We could.

But it's not his decision to make, and Watson has already made hers. She fixes lives and he deconstructs them. She will have to go as she does, as they all do, and leave him behind to figure out one more puzzle as she disappears into this impossible, improbable city.

He repeats her words back, then, as one last salute. It's all he knows how to offer as thanks, and he's more relieved than he thought he would be when she says you're so very welcome in every way but aloud.

Watson is not leaving, not yet, and Sherlock doesn't know what to say on this recent development.

So, defaulting: he doesn't say much at all. He plays the violin. He fiddles with locks. He rearranges the furniture. He takes down his crime scene analysis. He pins up a single notecard, written on it a single word: Moriarty, and stares at it until Watson comes to see what he's up to, carrying with her two steaming mugs.

She offers him one. "It's not tea," she says when he picks it up, sniffs it. "It's just hot water and honey. But my dad would give this to me when I was little, whenever I was sick or just needed company. It helped."

He doesn't break his gaze away from the wall. "I'm not sick," he replies, but neither of them address the other option.

Watson leans back on the table, staring at the card. "This is the man that killed," she pauses, as if now, of all times, she's worried about crossing personal boundaries. "Miss Adler."

"Irene," he says, and with it, permission. She'd had a beautiful name. She'd want it to be used.

Joan takes a long draught from the mug. Sherlock tries it himself, but the water is still so hot, he nearly scalds his tongue. He drinks it anyway.

"I don't know what happened in that warehouse," Watson says suddenly. She taps her fingers on the edge of the table, frowns a bit. "That is, I'm not as good as you probably want me to be. Figuring out where people have been and what they're doing and thinking. I don't know what you were thinking when you took Moran."

"Half of detective work is recognizing and accepting the incapability of unraveling every mystery in the world, Watson," he tells her.

"What I mean is." She turns to him with that familiar look: half exasperation, half knowing, somehow all still painfully familiar in a way that he's not sure he's ready for, yet. "I don't imagine I'll be so hard to leave behind next time. If you want me as your apprentice, you can't go running off on your own like that. We're a team."

Sherlock finally tears his eyes away from the notecard to glance at her before darting his gaze back again. Joan notices; she grins into her mug but changes the subject. "Well. More on that later." After another sip, she says, "I noticed you rearranged the furniture."

"An active mind rebels at – "

"Rebels at stagnation, yes, I know," she finishes. "I wasn't complaining. I was actually thinking, maybe this could be something. If I'm staying – well maybe it might be a long-term project, fixing this place up. There's tons of junk and things upstairs that need sorting out, not to mention the mess in the living room. Just, while we're waiting for your cases. We could rearrange it, make it a bit more… livable."

"Let's paint the walls first," he says quietly.

"Paint the… your dad won't mind?"

His father hadn't minded shipping his son to America, locking him away, sending an actor to check in on his progress with a sober companion he himself had hired to keep his son in check. A little paint won't make a difference at all.

"Grey, I think," he says.

"All right," Joan replies. "Maybe a soft shade. Enough to let the light in."

He nods distantly, then swallows. "I meant what I said, you know," he concedes after a long moment, giving in. Watson should've figured this one out on her own, really, but he'll give this to her, just this once. "To your mother."

Watson pauses. "You said you were just telling her what she wanted to hear."

"Nevertheless."

Joan nods. "Okay. I… thank you."

He doesn't offer more and she doesn't ask for much else. It's why, he thinks, it'll work, this strange fellowship; for he's as much of her companion now as she is one to him, and when he raises the mug to his lips again, the water has cooled, just warm enough to comfort as he closes his eyes and waits.