In the summer after Sherlock turns seven, their father has a truly unique idea. "I think the boys should meet other children."

He says it casually over dinner, as though it isn't the most ground-breaking idea he's had in years. The rest of them all have different reactions to this – their mother lets out a squawk of overprotective indignation, Sherlock freezes halfway through chewing and Mycroft...Mycroft feels his stomach leap with an emotion he hasn't felt for a long time – hope.

He's spent fourteen years at home. Home-schooled by their mother, surrounded by fields and trees, with no companions other than a ragged old dog and his stupid little brother. A brother so idiotic that he actually had to be taught deduction by Mycroft. An admittedly perceptive brother sadly so moronic that he couldn't even tell what their father's rubbed shoelaces meant before Mycroft informed him. It's from their father, Mycroft long ago decided, this slowness. Their mother is a genius, but a flaky genius too preoccupied with her youngest child to spend much time cultivating her talents. The whole set-up has been infuriating.

But now there is a chance to get out, to be among other intelligent people. People his age, with his skills. Mycroft could show them so many things. They could show him so many things. Other people with the same mind, with the same sharpness, people like Mycroft, people who aren't so backward

"Yes," he says aloud before their mother can get a word of refusal in. "Yes, I want to meet other children."

His father beams, that silly smile that Mycroft can't bring himself to get annoyed with, not this time. "Two votes already," he says, because he's always had this stupid idea that their house is a democracy, even though one of the voters is seven and an idiot to boot. "Sherlock?"

They turn eyes onto Sherlock. He has unfrozen, is chewing slowly, eyes distant. Eventually he swallows, then shrugs.

"Eh, I'll give that a half," their father says, undismayed by Sherlock's habitual indifference. He looks up beatifically at their mother. "You've been outnumbered, dear."

Their mother dithers rebelliously. "But we've been doing so well here, Sherlock's been progressing beautifully – "

"For an idiot," Mycroft puts in, earning himself a glare from the brat and a tut from their mother at this treatment of her favourite.

Father scratches his nose. "Nevertheless," he says. "I think it would be a good idea. They could make some friends." He glances sidelong at their mother, with one of those looks that Mycroft still hasn't been able to decipher, no matter how hard he tries. "It could be educational," he adds, with emphasis.

Their mother folds. It's astonishing how their father can do that. How does such a simple man have such an effect on the cleverest person Mycroft knows? It's a mystery, it truly is.

"Oh, all right then," she concedes. "But they won't enjoy it."

Mycroft knows she's wrong – he can't even be bothered to hide his victorious smile. Finally, he thinks. Finally he'll be free of this...goldfish bowl.

His father comes to see him when he's getting ready for bed. When Mycroft was very small, they used to read together before he went to sleep, silly books that were far above Mycroft's reading level, but he'd enjoyed the experience nonetheless. His father had a nice reading voice, very warm and gentle and relaxing. Then Sherlock had come along and things had gone a bit crazy because his parents hadn't actually expected to have another child, and somewhere along the line reading to Mycroft had been...forgotten. By the time his father remembered, it was too late and Mycroft was too old. He was left to read on his own now.

But tonight, when he comes into the room, his father is sitting on the bed. He's thumbing at some mathematical book, something that would no doubt be inexplicable to him but is child's play to Mycroft.

"Mycroft," his father says without looking at him, "About meeting those children..."

He hasn't backed down from the idea, Mycroft can see that in the shirt creases at his elbows, so it must be something else. He says guardedly, "Yes..."

His father glances up. Their are distinct lines of worry around his eyes, but Mycroft can't imagine what he'd be worried about. There are still things he can't read, but he's working on that.

"Just..." his father mumbles. "Just...don't expect too much, all right?"

Mycroft doesn't understand, and he hates not understanding something. He glances at the book in his father's hand. "Are you planning to read to me?"

His father blinks. "Would you like me to?"

Mycroft surprises himself with his answer. "No."

There is an awkward silence. His father looks down at the book, rubs a thumb across the faded cover, then stands up and hands the book to Mycroft. Mycroft takes it.

"Good night, son," his father says, then leaves.

Mycroft is left alone with his book. Like always.

Their parents discover there is a drop-in centre for children during the half term not too far from where they are, so it is agreed that both boys will try it out for a day. A few days after the announcement, when Mycroft is dutifully making footprints in the wet soil of their mother's favourite flowerbed with his father's too-large shoes so that Sherlock can examine the imprints, Sherlock says, "Why do you want to see other children? Why aren't I enough?"

"Because you're stupid," Mycroft reminds him, as per his brotherly duty. He steps into the soft dirt, feels it give way under his foot. "It will be nice to have some intelligent people around for a change," he muses.

Sherlock measures the footprint Mycroft has made with a ruler diligently. "They might not be intelligent," he says.

Mycroft snorts. "You see, Sherlock, those sorts of comments are exactly why I call you stupid."

Sherlock has no retort, which is rare, even for his limited mind.

The car trip to the drop-in centre is fraught with emotion. Mycroft is so excited he can barely sit still and Sherlock has slumped into a sulking lump, which is a complete reversal of their usual roles. Then there's their mother, panicky at the thought of leaving her two darlings to the ravages of other people's children, and their father, who keeps glancing at Mycroft with restless eyes. It's practically a relief when they finally get to the centre and their parents leave them to themselves.

They enter the room a bit awkwardly to find children of all ages, from five year olds to teenagers, socialising and playing games. Without further ado, they are dragged into a circle of chattering, gossiping people. It's loud and obtrusive, and Mycroft is momentarily stunned into silence. Sherlock follows suit for a bit, then, during a lull in the conversation, says suddenly, "The drop-in supervisor is going out with the cleaner."

There is a pause. Mycroft sees Sherlock draw into himself slightly, expecting a backlash of scornful remarks about the obviousness of his deduction. Mycroft himself saw it seconds within meeting the supervisor, he just didn't think it noteworthy enough to tell anyone else. Surely everyone already knew.

But from the looks on their faces, he can tell they didn't. One girl gapes at Sherlock openly. "How did you know that?" she asks.

Sherlock stalls. He glances up at Mycroft for either assistance or confirmation that he too heard the girl's strange question, but Mycroft is too shocked to do anything. Sherlock turns back to the girl. "Her sleeves," he mumbles. "And her hands. Didn't you see?"

The girl shakes her head. Another child says, confusedly, "I don't know what you're talking about."

"But it's obvious," Sherlock cries. It dawns on Mycroft that maybe the children are playing dumb, joking around with his stupid little brother, but one look at their faces tells him this is not the case. These children are genuinely puzzled.

A cold fear starts to unfurl in Mycroft's stomach.

When their parents come to pick them up at the end of the day, they find two very different children to the ones they left waiting for them. Sherlock is animated, more chatty and excitable than he has been in years, and Mycroft is pale and silent.

Sherlock spends the journey back shouting his astonishment to the skies. "They're all stupid," he yells. "Really, really stupid, not me-stupid. I'm not stupid at all. I'm really, really clever, I'm clever!" His eyes flash with the excitement of his revelation, and he practically bounces in his seat. "Mummy, they didn't even know what people's shoelaces meant, they didn't have a clue, did they Mycroft? They didn't know a thing, did they Mycroft?"

Mycroft says nothing. His voice abandoned him halfway through the day, just about the time he'd interrogated everyone, the adults too, and had found that yes, they were all that stupid.

Sherlock doesn't even notice this. "Mummy, I want to go back again. Can I go back again? I want to tell them all how stupid they are."

Their father hums a warning from the front seat. "Sherlock, it's not nice to tell people that."

Sherlock – a boy who has been told by his brother that he's a moron from birth – ignores this. "I want to go back," he insists. "I want them all to know I'm clever."

Mycroft can't eat dinner that night. It is the first time this has ever happened to him. He has always been able to clear his plate, no matter what has been put in front of him. But tonight he has no appetite. He stares blankly into his glass of water, half listening to Sherlock's repeated retelling of events.

They were all stupid.

All of them, even the adults. Stupider than Sherlock – far stupider by far. Everyone was...

"Mycroft," his father says gently, butting into his thoughts. "Aren't you hungry?"

Mycroft can't even imagine eating. He stares at his water. "Are they all like that?" he asks. "The whole world?"

"You mean..." his father says, then trails off. His silence is answer enough.

The fear that has been threatening to overwhelm Mycroft since the beginning finally gains the upper hand. For a moment he finds it hard to breathe. "They're all goldfish," he says aloud, and his voice is croaking. "All of them. All of th – "

He stands up, not quite realising he has done so until he is on his feet, then leaves the room abruptly.

He lies on his bed, listening to the almost indecipherable chattering of Sherlock downstairs. There have been many times when Mycroft has felt alone in his life – just after Sherlock's birth, when he was premature and sickly and his mother was so terrified for him, several straight years after that as well, the moment he realised just who was the favourite in his genius mother's eyes, the ever-nagging sensation that he was the cleverest person in the house, but this...this is a new loneliness all of its own.

He'd dreamt about leaving the house, getting out into the world and finding those of his kind. It was the only thing that had kept him going during those lonely moments. Abandoning the goldfish bowl and its goldfish. But now he's discovered the truth. The goldfish bowl isn't this house. It's the world. It's the entire planet. There is not going to be a single person in Mycroft's life who is as intelligent as him. He is doomed to be alone forever.

He's living in a world of goldfish.

The fear creeps up on him, crashes into him, and for a moment he feels like crying, even though he hasn't done that for years and years, not since baby Sherlock was brought home from the hospital alive and well. He folds his arms over his eyes, blocking out everything.

How is he going to live in this world? How can he possibly live like this? Leaving this house won't matter a jot, because outside it's all the same. Everything is the same and only Mycroft is different, he's the only one on the planet who is completely and utterly different. This feeling of's never going to go away.

He is briefly aware of the outside world, aware enough to realise that the sound of Sherlock's yammering has stopped. He takes his arms from his eyes, only to discover that the reason for Sherlock's silence is because he's hovering in Mycroft's doorway irresolutely instead.

"Go away," Mycroft says hoarsely, and returns his gaze to the ceiling.

"The supervisor wasn't just going out with the cleaner," Sherlock comments, a little hesitancy in his voice. "She was also going out with a man in India."

Mycroft wants to block his ears and stop himself from hearing this painfully obvious observation. Is this what it's going to be like forever? Constantly banal remarks from everyone around him? "So what?" he says.

There is a pause from Sherlock. "I saw it in her shirt buttons," he says. "They were done up wrong. And her hair – it's a style popular in India – she doesn't like it so it must be because he does. And I saw her fingernails – "

" - Were scuffed at the edges, yes, Sherlock, I know," Mycroft half snaps. "Just go away."

"And also her watch," Sherlock adds.

Mycroft blinks. He frowns at the ceiling, then sits up, looking at Sherlock properly. "What?"

"Her watch," Sherlock says. He fidgets, unsure. "It was ticking funny. It wasn't keeping time properly. I saw. Sometimes the second hand went back on itself. That means it was getting worn out, but the watch was new so I couldn't understand why it would be like that. Then I thought it was because she keeps abroad and she keeps changing the time on her watch, and the – and the time difference had to be big because it was so worn out, and I saw from her hair that it was India and I – well surely you saw that too?"

Mycroft stares. He didn't see that. He didn't notice anything about her watch at all.

A quiver of a grin starts to spread across Sherlock's face. "You mean you didn't see it?"

"I – no, of course I did," Mycroft bluffs quickly. "I just didn't think you would, that's all."

Sherlock is deceived. "Really? Does that mean I, um..." He tries to remember the phrase, a phrase he's never really heard directed at him before. "Exceeded your expectations?"

"I – yeah," Mycroft says, without thinking.

Sherlock looks like all his Christmases have come at once. Mycroft opens his mouth to put him down again, back in his place, but he seems to have run out of jibes for the moment. Instead he finds himself simply saying, "Go away."

Sherlock obeys, a skip in his step. Mycroft stares at the open doorway.

He's lonely, and he's going to stay that way all his life. He knows that now. But maybe there's one person – just one – who might be able to surprise him once in a while. Perhaps more than once in a while. Perhaps one day he'll do something incredible. And perhaps that's something for Mycroft to live for.

Sherlock had come into the world and practically ruined things for Mycroft from the beginning, and as a result Mycroft had never really wanted Sherlock around.

Not until now.