Sherlock is about to march into the living room and demand intellectual stimulation before he kills someone himself just for something to do, but he stops in the doorway at the sight that awaits him. John is sitting on his chair – nothing unusual there. There's a cup of tea (cold, Sherlock thinks, and for once he can't deduce why) – again, hardly an unusual occurrence in John's routine. But he is sitting with his head in his hands and Sherlock isn't sure, but there is a telling redness to John's eyes that suggest he's been crying.
He's never actually seen John upset. Happy, yes, and annoyed – well, more times a day than he can count, usually at him. But dejected as he is now, never. He's clearly visible from the doorway and he knows John will have spotted him in his peripheral vision, so he can't avoid the inevitable disaster that is his usual style when faced with anything resembling emotion. He knows he's got to say something, but what –
"She broke up with me, Sherlock." John says, sounding unnecessarily loud in the completely still room. His face crumples and Sherlock feels a twitch of annoyance. His latest girlfriend – Alice, he reminded himself, not that it mattered now anyway – had been around much longer than the previous ones; in fact, over a year. Sherlock had taken an instant dislike to her as soon as he'd overheard her whisper to John, all coquettish giggles and smiles, "He doesn't seem like someone you'd be friends with," and she rarely came to the flat. John had spent many nights at hers, coming home rumpled and gritty-eyed the day after with a smirk on his face that Sherlock finds insufferable. And if Sherlock wasn't surprised it hadn't lasted (they never seemed to, John's relationships), he was surprised to see John so openly upset by it.
He's uncomfortable. Reassurance has never been his strong point and he supposes that saying he was pleased wouldn't help at all, so he removes John's mug of tea and tips in down the sink, watching the milky beige normality of it wash away. The kettle begins to bubble quietly moments later and he still hasn't broken the silence as he sets another cup of tea down beside John. That's what people do, make tea in times of crisis, he thought rapidly, as he scanned his brain for anything that might be useful in this situation.
"Why?" Sherlock says, interested as always in the facts of a situation; but he says it as gently as he knows how, acutely aware that John looks sadder than he's ever seen anyone.
Oddly, this question draws a flicker in John's gaze, avoidance and a furtiveness he doesn't normally display. But he answers anyway, in a hollow voice, "It just isn't working. The same old thing."
Poor excuse for 'I'm sick of you', Sherlock thinks with a mixture of disdain and anger on John's behalf. "Oh." he offers. "There'll be other people. Girls." he adds lamely, unable to bring himself to utter "Plenty more fish in the sea", but sure the sentiment applies to nobody more accurately than John Watson. John shoots him a look of pure vitriol shot through with despair.
"That isn't the point!" he says, hotly, sounding uncomfortably close to tears. Sherlock flinches slightly at the raised tone and realises he has no idea what the point is. John has broken up with yet another woman who is dull, inferior to him and vacuous; Sherlock allows for the fickle hearts of ordinary people and yet still fails to see why John's should be breaking so obviously in front of him.
"I don't pretend to understand these affairs of the heart - ", he blusters, scrambling internally for something to say that will help, because the sight of John quite so crushed makes him feel uncomfortably like a weight is resting on his own chest. But John's eyes burn into his own, and then he spits, "No, you don't. At all." and storms out leaving the weight pressing down, Sherlock alone in the flat.
He doesn't mean to pry, honestly. But the piece of paper John has left on the table, crumpled in a way that makes it look like it's been carried in somebody's hand – John's hand – seems to Sherlock as though it could be a clue as to how to help John. The handwriting must be Alice's, a bold, round hand that looks too cheerful for the contents. He settles into a chair with John's tea and reads.
I'm sorry to write you a letter but I don't know if I could say this to your face. ("Coward." he sniffs, taking a mouthful of tea.) I love you, really, but this isn't what I thought it was going to be, I'm not as happy as I thought. You have one great love in your life ("Sentimental twaddle,") and I'm not yours, John. I've tried to ignore the feeling that your mind is somewhere else half the time and I've tried not to take it personally when you give me crap last-minute excuses not to see me, but it's obvious to me that, even if you haven't realised, you're in love with somebody else. I'd say you know who I mean but I don't think you have actually realised. Don't ring me for a bit, I need to get my head round everything and I think you'll find you have a lot to come to terms with.
Sherlock sits in silence but his brain kicks into gear, Alice's words making little sense to him. John's relationships were generally short-lived, yes, but he is nothing if not a man of morals and Sherlock is sure the idea of infidelity – emotional or physical – would be unacceptable to him. John would never stay in a relationship with someone if he had feelings for someone else – no, Sherlock notes with amusement, he'd simply end it and start another immediately, as he'd seen him do countless times. So who, then, was this person John was supposedly in love with? He hadn't been seeing anyone else – Sherlock would have observed it immediately, infidelity was so absurdly telling on a person – nor so much as mentioned anybody's name. He could ask, but thinks it might earn him a right hook for reading the letter and John has surprising strength for someone so short. He vows to observe John for signs and is recalling in his mind exactly where the letter was lying so that he can replace it perfectly when the door slams and John comes in, soaked from the rain and a look of horror on his face.
"My letter – you didn't?" he says, looking crestfallen. Sherlock looks at it as though it has just appeared in his hand, feigning surprise. "Oh. I, well I thought I'd see what it was, just a piece of paper lying around..." he trailed off, John's face suggesting that this ruse wasn't working.
"Oh, alright." He rolls his eyes. "I read it, but honestly I'm not bothered about your schoolboy crushes, I just wanted to know if there was anything I could do to help." He says the last part defensively, and he is surprised when John fails to explode in anger. Instead, he smiles sadly and shakes his head with what looks like wonder.
"Are you?" Sherlock asks, curious. John frowns, warily.
"Am I what?"
"In love with someone else? I'm sure I'd have noticed you mooning over somebody. And if you're not with Alice, you're with me. Which you're not lying about, because I'd know. So you can't have been seeing someone." He reasons this, ideas occurring to him as he speaks and becoming more confused. John takes three strides, snatches the letter and stuffs it in a pocket, his face twisted with an emotion Sherlock doesn't have the words for.
"No. I'm not in love with anybody else. She's wrong." he replies, and Sherlock thinks, as he hears John's heavy footsteps leading up the stairs, that he didn't sound sure.