Lost Baggage (or, alternatively, Finder's Keepers)

...

The first time they met, it was in the morgue. As Sherlock walked in with John not far behind him, they could hear two people laughing, and once they were through the door, they could see the sources of this laughter. One of them was Molly. The other, a ginger-haired man with his back to them, who looked just an inch or two shorter than Sherlock, wearing normal clothes. Jeans and a t-shirt. Simple and normal.

Maybe that was why John was so shocked when the man turned around only to have Sherlock's face.

Everything. The only thing to suggest that they were in fact different people was that this new bloke was a redhead with freckles. Everything else screamed 'identical twin!' like nobody's business.

Obviously the stranger had noticed this as well, because he was now exhibiting class A awkward behaviour. Stuttering and staring, looking back and forth between an embarrassed Molly who was red in the cheeks, and John, who didn't know what was going on either, and Sherlock.

Sherlock, who hadn't said a word.

"Er," John started, not quite knowing what you were supposed to say in this sort of situation.

He didn't get to say anything else.

"You," Sherlock had said, suddenly and without warning coming alive again after seeming to have turned to stone. Or at least, whatever it was that he'd been doing, since he obviously can't have been in shock, caught unaware or not.

The next moment, Molly and John watched as Sherlock took the man by the arm and started all but dragging him toward the nearest free room. "I think we need to talk."

The two left behind stared at the door, but then John shrugged, and asked Molly who the lookalike was, mostly from morbid curiosity.

"No one, really. No, I don't mean that, I mean - I just met him today. He had a few hours free in London. Airline pilot, you know. I'd have thought he was Sherlock, except Sherlock was with you and you'd just texted me about that case you two were on, so I knew he had to still be with you. Sorry, um."

John shook his head, and Molly gave him a worried look.

"It's nothing. It's just… weird, that's all."

"Yeah," Molly said with a nervous laugh. "Weird."

...

The moment they were in the room - classroom, not used since earlier this week, nothing dangerous or potentially hazardous, nothing deceased remaining - Sherlock let go of Martin's arm, and stared for precisely fifteen seconds. After this, he started to pace about the room, which only served to confuse Martin further.

"Um, sorry. Well, but. Why-"

"You're Martin Crieff-"

"Captain Martin Crieff, and how did you-?"

"All right, then. Captain." A twitch of Sherlock's lips suggested a smile of amusement, but nothing more. "And I'm Sherlock Holmes." There, he paused, an odd look on his face, as though he didn't quite know where to go from there. Which was actually quite accurate, since the truth was, he didn't.

"Oh. Then, would you mind telling me why...?"

There was a particularly pathetic manner to Martin, Sherlock found, that was evident even when the man was trying hard to be assertive. All in all, he found it to be at the same time irritating and confusing. But that was neither here nor there.

He cleared his throat, and stood still.

"I feel that I owe you an apology of sorts."

There. He'd said it.

Martin, however, clearly did not feel that this was an adequate explanation for his actions.

"I've never met you before in my life! And- and what's more, I think I'd know if I had! You've got my face!"

"Actually-" Sherlock cut himself off. Maybe that was a bit quick. How about... yes. "For your information, the incident I'm referring to happened more than just 'several' years ago, and you weren't at fault at all. Ergo, my apology."

Martin stopped flailing, just a bit. Not completely, but enough that it was obvious he was listening and he still didn't get it.

"I still don't understand. How could you have something to apologise to me for?"

"Because," Sherlock started, leaning now against one of the tables, eyes shuttered, "at the age of five I noticed certain odd things going on, and, being five, did not see any reason why I should not inform both of my parents at the same time."

"I... don't see what that has to do with me? Or, you know. Right here and now."

"On the contrary," Sherlock countered, "it has everything to do with you. After all - how was I supposed to know, at the age of five, that my deductions would lead to the discovery of my father's... affair. Mummy was most displeased."

Affair. That was it. Out into the open, as they said.

Martin found himself staring at this strange mirror-image version of himself, who was, as far as he could see, much smarter, much better looking and much more confident. If he were an airline pilot, Martin thought, no one would ever mistake him for the steward or the flight attendant. He'd always be the captain.

He found it somewhat ridiculous, being jealous of someone with his own face.

His... own face.

And... ohgod. He needed to sit down. He really- oh, chair. That was useful. He sat with a thump.

"So. You, uh. How?"

"How did I reach the conclusion that it was you? Apart from the fact that I distinctly remember the woman he'd met with being a redhead and the very singular fact that we look like long lost twins?" Well, that was a start, at any rate. "...Mycroft also has an interest in you, especially given my profession and your face. Before this, we didn't exactly walk in the same circles."

"...Oh."

'Oh'. That was a 'not good' sound, wasn't it?

"Those friends of yours don't know, do they?"

Sherlock snorted. "If they did, I would hardly have dragged you to the nearest place of privacy, now would I?" Not least because this way, it meant that the only witness to his moment of pride-swallowing was Martin himself.

Even so, Martin was having a hard time coming to terms with what he was being told.

"But. I've got to- why wait all this time? Or rather, why tell me at all? I was fine not knowing. You could've just... left it be. Or something."

"I told you I owed you an apology," came Sherlock's drawl. "Failing to explain why you were cut off from the potential support one of your parents might have been willing to give would have hardly fulfilled that requirement."

"...Oh." This time, it was quieter. Martin stood, legs wobbling somewhat. This was the first time he'd ever had a brother. This was the first time he'd been told he was the result of his mum's affair with what sounded like some rich bloke who'd been more or less happily married. "I think I need to, uh, think about this."

And with that he started out of the door. He was not running away. Airline pilots, Captains, even, did not run away.

He did, however, leave behind a very confused John Watson and an equally confused but also indignant Molly Hooper - who believed that he had scared away her new friend and potential boyfriend - behind, both converging on one Sherlock Holmes, wanting to know what had been said and what had gone on to cause such a reaction.

...

AN: Awkward Sherlock here is AWKWARD. It feels kind of OOC, but that's... bearing in mind that he's bringing up and bringing to the front of his mind an event that happened when he was five. Which I would say would be hard, and that it's a 'mistake' would make it even worse.