Sherlock used to think that the most important thing was to bring down Moriarty; save John from being blackmail material, save John from getting hurt.
That's already happened now. There's no going back; no stopping that first night in their apartment, or the one in Sherlock's bed, or the time John turned around and accepted.
But there are two years of friendship, two years of real connection because Sherlock knows with blinding certainty that John loved – loves – Sherlock, just as he knows that he loves John.
And so he doesn't bother with subterfuge, doesn't bother with anything. Moriarty knows that Sherlock's slowly but surely destroyed his networks, destroyed everything while he's been occupied with tearing down John; and so when Mycroft sets off a diversion that they all know is a diversion, Moriarty has no choice but to leave the house that John now lives in with him, grandiose and spacious and as far from the crowded warmth of 221B as is possible.
Sherlock doesn't bother with subterfuge.
He knocks on the door, finds it open, enters.
John's eating breakfast in the kitchen, already looking Sherlock's way when he enters. He doesn't move, he stills, every bone and muscle and tendon locking in place and then reactivating, ready for flight or fight or anything.
"I'm home, John," Sherlock says quietly, and then he wishes he hadn't because there's everything in those three words.
Three years, nine months and twenty five days. Rage, impotent fury, sorrow, regret, guilt, fear, horror, love.
All.
John tilts his head slightly.
"Welcome home, Sherlock" he replies, his own bundle of overpowering grief and joy and despair joining the echoes that Sherlock has left in the spacious room.
They don't embrace. But somehow, Sherlock finds himself sunk to the floor next to John, just under the stove, fingers entwined despite the good foot of space between them.
"Did you beat him?"
Sherlock nods, knows that despite three years, nine months and twenty five days, John will still register the movement as easily as he always has, as though when Sherlock moves he does too, just like Sherlock fancies he's felt every stroke of Moriarty's fingers, every thrust of his hips.
"Hmm." John's fingers tighten slightly. "Good."
"Will you leave him?"
"No."
He expected that, but it hurts just the same.
"Alright."
For three torturous, blissful minutes, he lets himself absorb the warmth of John's skin, the solid strength of his muscles. And then he pushes himself to his feet, looks down at his former roommate. "I'd best be gone before Moriarty gets back."
John nods. "Fair enough. I'll see you out."
They don't say another word till they're at the door and Sherlock turns to face his best friend with nothing to say, nothing on his lips or in his mind at all.
The shorter man's forehead creases in a frown, frustrated but amused with a surprising lightness that warms Sherlock's heart in a way that nothing has in almost four years. "Bugger this."
And then he reaches up, yanks Sherlock down to meet his lips too, too briefly.
"Dinner tomorrow at that Italian place you took me to that first night?" John asks gruffly.
What about Moriarty? Sherlock means to ask. It's not safe, he wants to add. You don't want me, rises to his lips, a bitter accusation that he knows isn't true except in a very specific, slight way that still rends at his heart.
Instead, he says "Alright. Eight o'clock?"
"Don't be late," John smiles wearily, as though he's sure Sherlock will be late anyway, the way he always is.
He doesn't close the door till Mycroft's car has turned the car, Sherlock knows. Hates John for it, almost as much as he loves him.