Set before The Empty Hearse, but no spoilers...a few references, but if you haven't seen the episode you won't pick up on them and they're not important. NOT Johnlock. The idea just kind of slapped me across the face tonight so I sat down and wrote this. There's a very loose plot, but mostly it's just a prologue to The Empty Hearse from John's POV. Oh, and I adore Mary, so I hope I wrote her OK too.

Enjoy. :) I don't own anything except my own ideas.

What Mary Knows

He thinks of Baker Street often. His new flat is nice—newer than 221B, and less cluttered, and always clean. His new flat mate is nice too—her name is Mary, and she puts the cap back on the toothpaste in the morning when he forgets and never does science experiments on the kitchen table. She doesn't even own a microscope, and she keeps things like broccoli and leftover pasta in the fridge; he hasn't seen a finger or foot that wasn't attached to a human body in months.

He has almost gone back to Baker Street too many times to count. When he takes a cab back from work the words are often on the tip of his tongue, but he always swallows them back and gives his and Mary's address instead. Sometimes it's an accident, almost saying the old place, and sometimes he thinks it would be good to visit…but he always changes his mind.

He's not ready for that yet.

Mary understands. They sit on the sofa in the evenings with the telly on in the background, and she tucks her cold feet under his thigh as she sketches and he reads (she hates socks, and is always barefoot around the flat—he finds it endearing, even when he becomes her unofficial foot warmer on cool nights when he's trying to read Dostoevsky and her cold toes slide under his leg unexpectedly). She does not often ask him about Baker Street or Sherlock, but when he mentions it she always stops whatever it is she's doing and fixes him with her beautiful, clear blue eyes and listens without saying a word.

He used to do that, he'd say when he'd come home to find Mary in her robe on the couch. Lay there all day until I got back to the flat. Wouldn't say a word when I came in unless it was something about being out of milk again.

His favorite, he'd say when Mary flicked through the channels and paused on a particularly horrid soap with sobbing women and remorseful men. He'd deduce who'd slept with who and who's kid was whose by how someone did her hair or whether the bloke was wearing a watch or not. He was brilliant, but he ruined the end every single time. Drove me up the wall.

Kettle actually used for tea, he'd say occasionally when he'd wake on lazy Saturday mornings and pad down the hall to a bowl of oatmeal and toast and a mug of tea made just the way he liked it. That's nice.

Sometimes Mary smiles softly at him, tucks her feet underneath her, cups her tea in her hands, and watches him, and he continues. The words never come easily, but sometimes he rambles haltingly for several minutes, memories filtering dustily through the barriers he's thrown up in his mind, until it becomes too painful and his voice fades away into the silence.

Mary always knows when he's exhausted himself emotionally, and she lets him sit for a moment with his own thoughts and pull himself together before she changes the subject without ever mentioning Sherlock herself. He loves this about her—loves that she seems to know that Sherlock is his, that the memories of Sherlock belong to him and him alone. He is slowly realizing that he wanted to spend his life with her, wanted to share everything with her…everything but Sherlock.

Sherlock was something different. That wild, manic, insensitive, wonderful man had been his whole life for those few short years, and the pain of watching him fling himself off a rooftop and drop down, down, down and not get back up, Sherlock always got back up, Sherlock had never been so still was still sharp and fresh in his nightmares.

He'd wake sometimes in the night with Sherlock's face in his mind's eye, and he would never remember what exactly he'd dreamed about, but there would sometimes be fresh tears on his face or an ache in his chest. He would lie awake trying to force the sharp, clear eyes and the glittering, fierce smile out of his head. Mary would wake sometimes too, and she'd lean up and look at him with a sad smile, and he would shrug helplessly as she tucked herself in securely next to him and traced circles on his chest with gentle fingers. He'd fall back asleep with her nestled next to him, feeling her heartbeat and wondering how he'd gotten so lucky to have such a beautiful woman in his life.

And because Mary never says Sherlock's name, he feels that the memories of Sherlock are being preserved. They begin to shut themselves away in his mind, and it is gradual and gentle enough that it is ok. Sherlock belongs to him, and Mary doesn't mind, and he loves her for it.

After all, he'd said one day, he's utterly impossible to explain unless you'd met him. There aren't words, really. You know?

She'd looked up from the novel she was reading and looked at him with those sparkling, gentle eyes and nodded.

Course I know.

They'd been sitting in silence, reading, Mary's feet in his lap, sipping hot chocolate and listening to the patter of raindrops on the pavement outside. The thought had come to his mind suddenly, and he'd said it without thinking. He'd looked at her for a long moment, and had the crazy urge to ask her to marry him, right then and there. He'd blinked and looked away, feeling the blush creeping up his neck, and she'd giggled softly.

Sorry, he'd said.

It's fine. Good book?

And just like that she'd brought the subject back to safer ground, and he'd felt an acute sense of relief that she'd chosen to ignore his blush. She'd noticed, he was sure—Mary always noticed. It is one of the many things that he finds so attractive about her. She is clever, Mary, and she notices everything, but she always knows when to mention it and when to keep things to herself. That is the difference between her and Sherlock, who'd never known when to keep his brilliant, clever, tactless deductions to himself.

I love you, he'd said quietly, after she'd returned to her book without another word. Her eyes had frozen on the page, and then slowly rose back up to his, and the sweet, adorable smile he'd fallen in love with the first time he'd met her had tugged at her lips.

I love you too, John.

Life is good. Life with Mary is better than he'd ever imagined it could be. Every morning he wakes with her tangled in the sheets next to him, curled up with the blankets half on her and half on the floor next to her (but he doesn't mind—she's consented to love him, and the least he can do is let her hog all the blankets), and he knows with increasing certainty that he can't bear to lose her too.

He thinks of Sherlock less frequently as the months pass, and one day he lets himself in quietly (Mary has beaten him home again—he'd had to stay at the office late) and comes up behind her in the kitchen. She's at the stove, humming a broken melody to herself and twitching her hips to the tune. He wraps his arms around her and buries his face in her neck, and she laughs aloud in surprise and nearly drops her spatula.

Mary, don't ever go anywhere, he murmurs. Can you do that for me?

Well, there's work, she laughs. And the shop. You aren't going to keep me cooped up in here all alone, are you?

Mmm, maybe, he says. He turns her around and presses a quick kiss to the corner of her mouth. I promise I'd come home to you every night, anyway.

I might be able to do it, then, she says, her face alive and bright, and he cups her face in his hands and kisses her gently. The sauce on the stove behind her begins to burn, and he lets her go reluctantly so that she can stir it. She casts him sideways glances as he leans against the table and watches her, and he can feel the silly smile on his face but doesn't care.

I'm being serious, you know, he says finally. His heart begins to thud against his ribcage, and it's almost painful but in a good way. About that.

Mary turns to look at him and grins shyly. So was I.

When they go to bed that night she cuddles up to him and kisses him goodnight, and he listens to her settle into asleep against his chest and realizes that he hadn't thought about Sherlock at all since he'd gone to bed the night before.

You're the best thing that could have happened to me, Mary, he whispers against the crown of her head, and she shifts slightly and murmurs intelligibly in her sleep. He smiles and presses a kiss into her hair. Will you marry me?

But she is asleep, and he doesn't want her to answer yet anyways. There is a proper time and place for that, and he thinks she knows that he wants her anyway. Of course she knows.

Sherlock would know too, if he were there. He'd deduce it with a single look, and probably do his best to sabotage the moment out of sheer tactlessness. But then, if Sherlock were here, he might have never met Mary in the first place. For the first time he wonders if Sherlock's death hadn't been a blessing in disguise, and then he feels horribly guilty and apologizes to the memory of a dead man in his head. Of course he'd rather Sherlock were still alive. He'd begged him to still be alive. He'd wanted it so badly it had made him sick, but it hadn't brought him his best friend back. And now he has Mary.

Yes, he thinks of Baker Street often, but the sting fades as Mary slowly heals him with buttered toast in the morning, kisses in the evening, and laughter and walks in the park and cold toes in between. He thinks that Sherlock would have liked her, and once he decides this there is nothing more he is waiting for.

So he goes out and buys a ring, and as he stares at the delicate golden band with the triple diamond setting—the promise of a future with the woman he loves more than he has ever loved anyone before—he thinks that Sherlock would have approved. He might have even consented to be best man, just for him, and he has to choke back a sob of laughter at the thought of his crazy, wonderful, completely insane best friend organizing a wedding and showing up in his dressing gown, or arriving an hour late for the ceremony, flushed and pale with the thrill of a case that just couldn't wait. The laughter threatens to turn to a real sob, and he closes his eyes tightly for just a moment as the shop owner watches him in embarrassed concern.

He pockets the ring and leaves the shop, and when he returns home to Mary he gathers her up into his arms and holds her close, and she simply holds him back and lets him breathe her in. In that moment, he does not think of Baker Street.

In that moment, he holds his whole world in his arms and he thinks only of Mary. A thin, pale man with thick, dark hair and ice-bright eyes runs through his mind, an imposing, familiar silhouette pounding in achingly familiar, wild abandon…but it fades in his memory as he presses a kiss to Mary's forehead and ignores the question in her eyes. He brushes his hand against the ring box in his pocket and smiles a secret smile to himself, and as they sit down to dinner and they laugh and talk and the box is a hard lump against his hip, he does not think of Baker Street.

He has everything he needs right here.

Aww...he has everything until Sherlock comes back, of course. :) Which, I must say, they couldn't have done better in the episode. It was pretty much perfect.

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