My body tenses up and my pulse elevates and I know it is him, I can pick out the hang of his coat and the cowlick at the back of his head from anywhere, from the busiest London sidewalk and certainly from this sparsely crowded market. Part of me mutters a disbelieving litany, it can't be him it couldn't be him, but that thought is soon squashed, because why couldn't it? It has been over two years, after all, there's no reason he couldn't be back, no reason he couldn't be here on this street, even if the odds are unlikely.

John is looking at me, and I shove a brown paper bag into his free hand and tell him to go back to the flat. I know he will not listen to me, he never does, but now is not the time to explain Victor Trevor to him, it's the time to dash off after that shabby brown coat, purchased four years ago from a charity shop, cigarette burn on the left sleeve.

If there was anything John Watson had learned in his two years with Sherlock, it was that when he ran off without explanation something terribly interesting was about to happen, and if you missed out on it it was your own stupid fault. He waited until Sherlock had loped about a block away, and then quickly followed after him, juggling the shopping as he ran. The eggs, he thought, were certainly done for.

They had only gone a few blocks when Sherlock finally slowed down to a brisk walk. Judging by the way he kept nervously glancing at him, his target was a young man in a shabby coat. He was tall, around Sherlock's height, Sherlock's curly mop obscuring the defining inch or so. Solid build, light brown hair brushed back from his forehead in waves. Handsome in a rather unremarkable way, John concluded. Sherlock passed him by and whipped out his mobile, pretending to text, slowing down enough to bump quite naturally into the young man he'd been trailing. Clever, John thought.

John's pocket buzzed. "Might be late," his phone said.

He is surprised to see me, but I flatter myself in concluding that it is not unpleasantly so. The familiar citrus scent of his aftershave cuts through the damp air, bringing with it a thousand moments I am incapable of deleting, Cambridge and the woods near his father's house and our dingy London flat, but I cannot let this catch me, not right now. Box it up and shove it away in the dark, to fester and grow roots. If I want nothing to do with those six years, what am I standing here for, raking my eyes over his square jaw and light brown eyes and the pale single freckle dashed on the bridge of his nose.

"Sherlock," he says, "I didn't expect to run into you."

"I lived in London three years ago," I say, my hands shoved into my pockets, "One might safely assume I'd live here still. You're the one who left." I want to bite my tongue at that little slip, because that's the crux of it, isn't it, Victor Trevor? You informed me that I never loved you and you left for Germany to learn to make terrible films, and I hated you for it.

"You're looking well," Victor says. He is rubbing the back of his neck the way he always does when he's nervous.

"I look the same as I always have," I tell him.

He smiles. "No you don't," he says.

No I don't, I allow.

John couldn't tell what they were saying, not over the din of the street, not from a safe distance, anyway. Small talk, probably, or at least as valiant an attempt as anyone could make with Sherlock. They looked awkward as anything standing there, avoiding looking at each other. Something was going on, or rather, had gone on, but John couldn't quite put his finger on it, not until the young man stroked Sherlock's cheek with his thumb, fingers lingering on his jaw.

Sherlock stood there for a moment, a look on his face unlike anything John had seen on him before. Something almost like love, perhaps, or maybe confusion. Were they really so different? John remembered that night at the pool, I've been reliably informed I don't have one, and Moriarty's smirk, We both know that's not quite true. Now John wondered if maybe he too had caught this expression, sometime in the past.

Sherlock smacked the young man's hand away and stepped backward. It was most definitely confusion now, and anger, real anger, a true rarity. The young man tried to grab Sherlock's hand and was rebuked almost violently; John wanted to jump out of hiding and take Sherlock away, back to the flat, but he held himself in check. Sherlock, clearly disgusted, turned on his heel and set off down the road, in the direction opposite Baker Street.

I have walked unthinkingly to our old flat, Victor's and mine, and I am furious with myself for it. The old peeling doors have been freshly painted, but aside from that the building looks the same as the day we moved in. The new tenants, I note, have not even changed the curtains; thick brown drapes hang heavy across our old window like dead things, blocking out the sunlight.

I finger the set of keys in my pocket. If they couldn't be bothered to change their window trimmings, certainly the locks had escaped their attention as well. I remember the little packet stashed in the moulding, the one I decided to leave as a house-warming gift to the intrepid. I didn't want to take it with me, though I took three others, hidden in little cracks and crevices at Baker Street. I haven't touched them, not yet. I don't want to start today, and I don't want to climb these steps and fit the key into the unchanged locks and pry the moulding off the wall in the bedroom.

I take my hand out of my pocket and rake it through my hair. It makes no sense what you turn me into, Victor Trevor.

"John!" Angelo greeted enthusiastically. "Alone today, I see. I'll get you your usual."

"No, no, I'm not... I wanted to talk with you a moment," John said, shifting uncomfortably, "if it's not too much trouble."

"Aye, sure," Angelo said. "Come give me a hand in the storeroom and you can talk my ear off."

John followed Angelo into the back. He'd been here a couple of times before, when Sherlock hit Angelo up for his particular brand of ex-con intel; usually John would do the heavy lifting while Sherlock perched on a cardboard box and interrogated. Play to your strengths, he would say.

"When Sherlock and I first came here together," John began, "You thought-no, assumed, I suppose-you assumed we were... together."

"And I apologized for that," Angelo said, grinning. "It'd just been so long for him, I'd hoped he'd found someone new."

"So there was someone?" John asked, "Before we met?"

Angelo stopped and gave John a long, scrutinizing stare; John could feel himself beginning to blush. And then, without warning, Angelo began to chuckle. "I wager you met the ex then?" he asked, a mischievous twinkle in his eyes.

John didn't follow me, so he's probably at Angelo's if he's learned a single thing from me, and he probably has a name by now. What shall I tell him if he asks me? I should have told him the story before, showed him the cryptic email and given him something harmless to blog about. He would have understood the things I didn't tell him. Perhaps I would have never chased after that jacket.

I open the packet of cigarettes I bought from the corner store and let one dangle from my mouth, unlit. "I was wrong," he said when he stroked my cheek. How is one to respond to that?

"He moped around for months," Angelo said, "and then about four or five months afterward all of a sudden he comes in and everything's right as rain, like he just decided it never happened. I thought to meself, ah, he's finally met someone new. When he brought you by I thought it was you."

"We'd only just met, then," John said. He was sitting on a crate of tomatoes, staring at the floor. "I had no idea."

Angelo snorted. "Now you're thinking, ah, that explains it, doesn't it? Why he is how he is."

John looked up and grinned weakly. "Nothing explains Sherlock Holmes," he said.

I am curled up on the sofa when I hear John's heavy tread up the steps. The door swings open and he calls out "I dropped the eggs, it's toast tomorrow morning." I say nothing, curling myself up more tightly, pretending to have fallen asleep.

He cut a rather pitiful figure, John thought, curled up on the sofa like a wounded animal. John walked to his chair, hesitated, and made instead for the gap at the edge of the sofa. "Shove over a bit," he said, pushing Sherlock's feet out of the way, "I know you're awake."

"I am not," Sherlock mumbled, but he moved his feet anyway.

"Anything good on the telly?" John grabbed the remote and flipped through the channels. "Top Gear repeat... oh, it's the one where they build caravans, you liked that one."

"Wake me when Hammond's catches fire," Sherlock said.

John sits there and doesn't say anything, doesn't ask anything. I am, admittedly, at a loss. Doesn't he want to know, need to know? He can't have the whole story, not yet, because only I know it, not Angelo or Mrs Hudson or even Victor Trevor, they don't know all of it, not the pieces of importance.

Perhaps this is one of those things about the social contract John always teases me for not understanding.

"My hands trembled when he left," Sherlock said, and it took a moment for John to realize Sherlock was talking to him, about him. Sherlock turned a little, just enough so he could see John's face. "Do you suppose I really was in love?"

I don't know why I'm asking, but I know I want to. The words have dropped from my mouth before I can bite them back, because I have to know what he thinks, and what he knows. He smiles at me.

"Stranger things have happened," John said, and that was enough.