"Round and round the garden, like a teddy bear…"

But Sherlock had played this game too many times to not realise what was coming next. "Don't tickle me!" he squealed, pulling his hand away from Mycroft's with a grin, then scrambling to his feet and darting toward the door.

Mycroft reflected that it was a good thing they were alone on the second floor. He was thirteen now, and quite tall for his age; voice on the verge of that first break. Far too old to be playing nursery rhymes with his almost-three-year-old brother. But he was home for the summer holidays, and had no friends living close by; one had to make do with what one had, and he had a brother on hand.

"I won't, I promise," he protested, trying to keep a straight face. "Come back."

Not for one moment imagining that Mycroft was telling anything other than the truth, Sherlock sat down in front of him again. He was trying to cross his legs, but hadn't quite figured it out yet, so they were bent awkwardly in as close an impression as he could get. Mycroft took his hand and drew an imaginary circle in his palm with his forefinger.

"Round and round the garden, like a teddy bear… one step…"

Sherlock looked up at him mistrustfully through his thick, dark curls.

"Two steps…"

Sherlock squealed and ducked out of the way just in time. He didn't realise that the point of the game was to be tickled, and had decided that the point was to avoid being tickled as much as possible. Trust Sherlock to put his own spin on things. Conventional thinking was not this kid's strong point.

"Mycroft!" Mummy suddenly called peevishly up the stairs.

Mycroft froze.

"Mycroft Linwood Holmes, I am talking to you."

Leaving Sherlock sitting instinctively hushed and still, Mycroft opened the door quietly and stepped out onto the landing. Mummy had come from the downstairs sitting room and was standing at the foot of the stairs.

"Yes, Mummy?"

"How many times do I need to tell you to keep your brother quiet when I have a headache?" she demanded.

Migraine. Again. She had a wet washcloth on the back of her neck.

"And yet, from the sounds of things, you're going out of your way to encourage him. That ridiculous squealing is going straight through my head."

"Sorry, Mummy."

"'Sorry' after the fact is not remotely the same thing as not bothering me in the first place. I have a lot on just now, apart from a towering migraine, and I asked you to look after your brother so he wouldn't disturb me. If he wants to shriek like a banshee, take him somewhere I don't have to hear it."

"Yes, Mummy."

Mycroft went back into the play-room, where Sherlock was sitting on the floor in what he hoped was a perfect imitation of his brother. Sherlock thought Mycroft was the pinnacle of humanity and everything he did was to be envied and emulated.

"Mummy's angry," Sherlock commented conversationally. "At Sherlock?"

"No, Sherlock. Mummy's not angry at you." But Mycroft knew that Sherlock had heard the entire exchange with Mummy and, furthermore, had understood every word of it, including migraine, which he knew as gwain. He knew that when Mummy had a gwain, it was a very bad idea to go anywhere near her or make any kind of noise at all.

"We go to the park," he suggested optimistically. "And see the ducks?"

Mycroft smiled.

"All right. But you have to put your clothes on first." It was a warm afternoon, and Sherlock had been running about the house in little more than a pair of rompers. "Go and fetch them, and your shoes. Quietly."

Sherlock was surprisingly stealthy, especially in bare feet, and returned from his bedroom in less than a minute, dragging behind him a pair of brown corduroy trousers and a blue t-shirt with a dinosaur printed on it.

"Shoes and socks, Sherlock."

Another trip to the bedroom, and Sherlock returned with white socks and a pair of trainers. He'd managed to pick matching shoes this time, which was a first that Mycroft was rather proud of.

"Help?"

"No, Sherlock, you're too old for help. Put them on yourself. Zip and dinosaur go in front, remember?"

Mycroft watched as Sherlock struggled with his trousers. Putting his feet in the wrong leg, or the same leg; stepping on the insides of the cuffs. And rapidly becoming very annoyed by his own lack of fine motor skills.

"Can't!"

"Sherlock, if you throw a tantrum we're not going anywhere," Mycroft told him. "Look at the trousers, look at your legs, and think how you can put them on properly."

Sherlock sized up both legs and trousers; decided the most efficacious method of putting one inside the other was to sit down, legs outstretched, then pull them on that way. Mycroft pulled him to his feet so that he could pull them to his waist, then gave in and helped him with the zip. Sherlock had less trouble with the shirt. Dinosaur in front.

"What this, Mycroft?" Sherlock was pointing to the dinosaur.

"It's a Tyrannosaurus Rex, Sherlock, but they didn't really look like that. I'll show you a picture in a book one day." Mycroft was tying one of Sherlock's shoes while Sherlock was yanking on the other, having put his socks on all by himself.

"Ready?"

"Right. Only took you half the afternoon. Come on. Quietly."

One of Sherlock's very first words had been quietly.