"Kittens, John," Sherlock says. "Kittens."

John surveys the scene in the living room. "Yes," he says. "I can see that."

There are twelve, no, thirteen kittens running around, at John's best estimate. It's difficult to count them because they keep darting in and out of sight, hiding under the sofa or between the cushions or behind Sherlock's legs. Sherlock himself is sitting cross-legged on the floor, like some kind of thin, curly-haired, English Buddha, and holds one black kitten in one hand and one white kitten in the other. John wouldn't be surprised if Sherlock turned out to be hiding more under his coat.

Since Sherlock doesn't seem inclined to venture any more information about what's going on, John shoos the kittens away from his armchair and sits down. From the floor, the kittens look at him reproachfully.

"How did this happen?" John asks, ignoring the kittens. He's not picking any of them up. He's definitely not caving in under the pressure of their big blue eyes. He's not. Part of him is still hoping against hope that those kittens are a vital clue in one of Sherlock's cases. He's got no idea of how thirteen kittens could fit with a murder investigation, but it's surely better than the alternative, which is that this morning Sherlock robbed a pet store. Maybe he should have listened when Anderson warned him about Sherlock.

"I'm not a psychopath," Sherlock says, scratching one of the kittens between the ears.

"I didn't say anything!" John complains.

Sherlock scoffs. "Please," he says. "Your train of thought is more than obvious." Then he proceeds to explain in minute detail how he knew what John was thinking about, just with his skills of observation. Halfway through, John loses track of what the detective is saying and instead stares at a kitten who's trying to unravel Sherlock's scarf with its tiny claws. The scarf is winning, much to the kitten's dismay.

"All right," John says when Sherlock pauses to catch his breath. "I believe you, you're not batshit crazy. Then I suppose there's a perfectly good reason why we have thirteen kittens in our living room."

"Fifteen," Sherlock corrects him. He doesn't venture any reason for the kittens, good or otherwise.

John groans. "Sherlock! Why are there fifteen kittens in our living room?"

"Because I want to keep them," Sherlock sniffs.

Eventually, though, the threat of forced feline eviction gets to him. Sherlock is lucky that John is so remarkably well-adjusted, otherwise he would have already been booted from the house along the kittens.

"I bought them," Sherlock explains, wrapping his hands protectively around the nearest kitten. "When you sent me to buy milk. I saw them and bought them."

John is impressed that Sherlock remembered about the milk. He'd only been trying to get the other man to do grocery shopping for about a year. "Fifteen kittens, though? Where did you even buy fifteen kittens? Not at Tesco, I hope."

Sherlock hoards the kittens closer. "From a man in the street," he replies. "He was selling kittens and I bought them."

One of the kittens, a calico critter smaller than Sherlock's fist, mews in protest at being crowded against Sherlock's chest. John rescues him before it's squashed. "Right, man on the street, that's not suspicious at all," John says.

He gets a scathing look from Sherlock in return for the sarcasm. "Do you take me for a fool?" asks the man who went to buy milk and got home with fifteen kittens.

John takes a deep breath and pets the kitten in his lap. It purrs happily. "I understand if you wanted a pet," he says. "But... fifteen? What are you even going to do with fifteen kittens?" He's hit by a sudden, nasty suspicion. "You aren't going to use any of them for your macabre experiments, are you?"

Sherlock looks outraged at the idea. "Of course not! I simply like having them around. They make boredom more tolerable."

They watch one of the kittens amble across the carpet and bump its nose against one of its brothers or sisters. Sherlock looks almost fond.

"All right, we can keep two or three ," John concedes. "Maybe Sarah can help us spread the word at the surgery, see if there's people who want to adopt a kitten..."

"No," Sherlock says. "We're keeping all of them."

"Sherlock..."

"All of them!" Sherlock exclaims, so forcefully that many of the kittens are startled and run away from him.

John sighs and pets the kittens. "I suppose it's better than the time when you shoot holes in the wall," he says.

Later that day he has to go out, because Sherlock forgot to buy milk.