A/N: Wrote this so long ago, before S3 aired, so it is (mildly) canon divergent. Anyhow, Sherlock's reaction in this is bizarre I know, it was just a weird little what if fic that's rather silly and random but I hope someone enjoys it anyhow.
Lestrade has known Sherlock for years and about as much interest as he's paid anyone is when they're dead. Except John. He'd wondered if Sherlock liked John, mused over it and whether he should ask John at the pub. Only it seemed wrong to ask a grieving friend to reveal if he might be a little more than that. Lestrade decided he honestly didn't want to know. Better that way, papers couldn't hassle him for gossip he didn't know.
When Sherlock came back 'from the dead' he seemed the same, more or less. A bit more prone to appreciating John perhaps, in his own bizarre manner. A bit softer on the insults to the Yarders like him as well, which Lestrade wasn't sure what to make of. It might just've been Sherlock thought he was getting on and was making some allowance for that. So that didn't last, not after he made a point to try and show Sherlock up. But not taking John for granted seemed to stick. Anyone who didn't know them would never spot it, subtle as it was. He saw the same with Mrs Hudson too.
It took him a while to place what was different about Sherlock in the morgue. He was being more inclusive with Molly. Molly actually had some useful points, not that it was a surprise to him, but to Sherlock maybe, and that's where Greg caught him out. Sherlock was letting the girl speak up, teasing out her intelligence. Every time Greg was there - roughly once a week – she seemed more confident, gone was the stammer.
It wasn't long before she made little jokes here and there (bad ones usually), gallows humour. Greg would smile or chuckle a little despite himself on occasion and Sherlock would be polite – ha, he hadn't thought he'd see that day - but generally ignore them, moving swifty on.
Except this time he didn't. At 5.42 am on Saturday, Greg Lestrade, heard Sherlock Holmes laugh, deep and low, heartily, and he kept on laughing, descending into sort of strangled giggles. Even Molly had to stop and looked rather concerned.
"It wasn't that funny, Sherlock."
"Yeah mate, you sure you haven't licked something dodgy at a scene? Poisoned yourself maybe? This isn't exactly like you."
When Sherlock finally got his composure back, barely contained by the looks of it, his explanation didn't do much to enlighten either of them.
"I know. So not me! It's amazing, and no, Molly, don't ever tell that joke again. It was horrendous, a tragedy upon the comic abilities of the whole human race."
Sherlock got up, a shallow snigger escaping as he strode over to his coat, "By the way, Mr Gare – poisoned with antifreeze, I think you'll find, once the tox screens come back. The bartender at his club did it. Contrary to popular opinion they're the worst secret keepers, you should never bare all with them. Especially when it's your wife they're having the affair with."
He was out the door like that leaving Greg with an equally bewildered Molly.
"Don't ask me. You know him better than I do," Molly replies to his questioning look.
"I'm not sure that's true anymore, the amount of time he spends here. From what I hear."
Molly zips up the bag with a cheerful demeanour. He's never managed to feel at home, or even passably comfortable, around dead bodies himself and doesn't know how she does it.
"He's all about the work," she says nonchalantly.
"So he says. Listen, when he's here, how often is he actually on a case?"
"I dunno. I don't tend to ask. Doesn't make much difference either way."
Greg supposes it probably doesn't matter to her, whether Sherlock's whims she indulges are practical or theoretical; Sherlock won't be any less insistent if it's purely for his own interest, but there's something nagging at the back of his mind about how Sherlock is changed around her.
"Perhaps not."
He's been waiting on the doorstep of 221 for 15 minutes with no response to his phonecalls or text messages when John gets back from Marks & Spencer and takes pity on him, letting him into the hallway.
"Been waiting long? Surprised to find you here."
"I wanted a word with Sherlock."
"Let me guess, he doesn't want a word with you? Or he's too lazy to get the door and knows you'll wait."
John unlocks the flat door and motions him in, "What did he do now?"
"I'm not sure. That's what worries me."
"Detective Inspector, I don't have an explanation for you."
Sherlock sits idly plucking at his violin, a position Greg has seen him do before when deep in thought. Right now, Sherlock is carefully looking past him, an unfocused gaze on the unlit fireplace, not meeting his eyes. Avoidant for some reason he hasn't uncovered properly yet.
"I don't believe you. In some ways I'd like to believe you were under the influence of something but I don't think that was the case."
"Hang on, what is this about?" John says, baffled, as he steps back into the room with a cup of tea, "Someone? Anyone?"
"Lestrade's curiosity has got the better of him, but he's wasting his time. And mine," Sherlock says pointedly, finally looking to him sharply, clearly expecting him to drop the issue when no further explanation has been forthcoming.
"I'm sure I'm not the only person who wants to know why you burst into a laughing fit at the mortuary this morning."
"Oh, that," says John, as if it's all become clear and unconcerning suddenly. He moves back towards the kitchen, making a beeline for the forgotten shopping bag.
"Wait, how do you know? Did Sherlock mention this to you?"
"No...but he did come home in intermittent hysterics. Rather contagious. Took a little while to calm Mrs Hudson down too."
"Well, Sherlock? I know the joke wasn't funny, so what is?"
Sherlock is now staring out the window, but glances towards him briefly and Greg catches a glimmer of a smile quirking at his lips, like he's remembering just what was so amusing.
"I didn't get it. I didn't understand it at all."
Sherlock's reply is softly spoken, as if it's difficult to admit and Greg has to strain to hear, stepping nearer so as to not miss anything more of the evolving discussion.
"Didn't get what? The joke? I wouldn't have thought that was new for you..."
"No, no!" Sherlock says with a hand wave dismissively, "There are plenty of jokes I fail to see the humour in. What I don't get is her. I don't understand her brain. Most of the time she's exactly like all you insignificant little people milling out about there and then there's a flash, like burning magnesium in a swimming pool, a surprise."
Greg starts laughing then because he gets it too suddenly. Right on cue John walks back in with pack of fancy biscuits he'd obviously forgotten to bring through at first, having missed most of Sherlock's revelation.
"What? No, really, what the hell is so funny?"
Sherlock smirks at Greg guffawing before turning back to the window to supposedly study the street outside.
"Nothing you need concern yourself with John."
Greg manages to take a breath and can't resist piping up there, "At least not until he asks you for advice."
He can sense, rather than see, Sherlock's scowl.
"That'd be something. What's he going to come to me for advice on?" John asks, still seeming somewhat exasperated at not being in on the joke.
"I can't say. It's priceless. I don't want to ruin the surprise. Boy, do I wish I could be there though."
"Ignore him, John. I won't need your expertise. I think you've proven you're not half as successful as you first appeared in that area."
"There's no way you're getting away with insulting me about something and not even telling me what it is -"
"I can see myself out," Greg says, now sufficiently recovered and eager to escape their bickering.
"Please do!" comes in unison from the duo.
He shuts the door behind him, torn between eavesdropping in case John gets clarification out of Sherlock, and legging it the hell out of there.
He has half a mind to go warn Molly of the chaos that might be brewing, save the girl – no, woman, he corrects himself, thinking of the change in her lately that made it more obvious – some trouble but he gets the impression any trouble would be short-lived and fairly well received. For all his foibles, when Sherlock did something, he did it to the best of his ability. He still wasn't a good man in the traditional sense, not quite there yet, but he was becoming a good enough one around Molly and there was no missing that.