It must be said, first of all, that Sherlock didn't like John.
This had several very excellent reasons: John had just turned four while Sherlock was only three-and-a-quarter and was, therefore, well outside Sherlock's social circle (which only included Teddy the plush squirrel anyway). John's parents both worked for Mummy, so Sherlock was obviously way more important than John. John wanted to be a ninja when he grew up whereas Sherlock was going to be a pirate; clearly, they were destined to be mortal enemies. And finally, most importantly, John had a blanket instead of a squirrel.
Blankets were stupid.
So on most of the days his parents didn't exile him to the nursery, Sherlock grabbed Teddy the squirrel and a dictionary and a packet of chocolate cigarettes and toddled off to hide under the creaky stairs in the east wing until he'd learned twenty-six new words, starting with A. He knew that John was around somewhere, but since that somewhere usually involved the garden and a lot of running and shouting and pretending to be a ninja (really, someone should tell John about stealth), Sherlock didn't pay him much attention.
Until That Day.
That Day started like any other. Sherlock had already learned abominable (causing great dislike; hateful), bore (a dull uninteresting person whom other people quickly become tired of), consequence (something that follows from an action or set of conditions), deceitful (tending to deceive; dishonest), evidence (sth. that gives proof or reasons to believe or agree with sth.), fiddle (a violin), and garrotte (a wire which might be tightened around the neck to prevent someone from breathing and so kill them) when he was interrupted for lunch, which mainly consisted of peas.
"Tha's abomimble," he informed Mummy, who merely kept studying her papers and muttered, "yes, dear."
If Mycroft hadn't been at school, Sherlock would have thrown his peas at him. That way they'd at least have served a purpose. As it was, he had to eat the abominable things before he was free to go back to the creaky stairs.
Only, someone was already there.
John had crept into the farthest corner so that it looked like he was wedged in there, with his knees drawn up all the way to his chin. He blinked at Sherlock from red-rimmed eyes and, after a moment, gave him a watery smile.
"Pissorf," Sherlock said politely, having learned from the gardener's daughter that the term could be employed to tell someone to go away.
John hesitated, then he nodded and started to crawl out from beneath the stairs. He had, Sherlock saw now with a sudden burst of rage, been pressed up against Teddy.
"Whe's your bwanket?" he demanded. Teddy was Sherlock's. Teddy was sacred. Teddy was something that John couldn't have.
"I dunno," he said. His lower lip wobbled a bit, but he didn't cry. Sherlock couldn't remember John ever crying. He did look very sad, though.
"Then go look," Sherlock said, exasperated. Really, it was the obvious consequence; John's brain had to be very tiny not to see that.
John sniffed, and nodded, and went away.
Sherlock made it all the way through half-wit (a stupid person), imbecile (a stupid person), and jerk (esp. AmE: a stupid person) before he snapped the dictionary shut with a huff.
Honestly. John's moping was distracting even when he wasn't there. Or maybe it was the lack of shouting outside. It was what they did: John ran around and laughed a lot while Sherlock sat and quietly hated the world. How dare John do something else instead?!
He found John in the library, huddled up against a bookshelf with his chin pressed to his knees again. If anything, he looked even more miserable than before.
"Bwanket?" Sherlock asked. If the stupid thing was still gone, he'd just have to find it. This much moping had to be boring.
"Wash," John said sadly.
Sherlock remembered when he'd left the chocolate cigarettes and Teddy in the sun, back when he'd still hidden under the west wing stairs, and the one had melted into the other and Teddy had been gone for two whole days before Mummy returned him and he'd been clean and fluffy and smelling all wrong. That had not been good.
He patted John's knee in quiet sympathy.
"Stay," he said. It worked on Mummy's dog, so he saw no reason why it shouldn't work on John. He waited until John had nodded, and then he took off.
One of the linen closets was just down the hall. Sherlock pulled out one of the woollen blankets that went into the guest rooms when it was colder. It was heavy and smelled of lavender and made him sneeze as he carried it into the library.
He dropped it at John's feet.
John blinked, and shook his head. "No. Sorry," he added, curse his mastery of the letter R.
Undeterred, Sherlock shrugged and took off again. Of course John wouldn't be satisfied with any old blanket, just as Sherlock wouldn't be satisfied with, say, a Teddy who was a rabbit instead of a squirrel. He simply had to find a better quality of blanket.
Cook's duvet was new. Sherlock had heard her telling one of the maids how obscenely expensive it was, but absolutely worth it. He'd looked up obscene (offensive to accepted ideas of morality) that day and been a little awed. That duvet had to be very special. Up close, it didn't look like much, but Mummy had already told him that looks could be deceiving so that was alright.
"No," John said. He'd taken out one of the chocolate cigarettes Sherlock had left with him and was picking off the paper. His fingertips were all chocolate-y.
"Itsa good bwanket," he protested.
"'s too big," John said.
Well. That was a fair point. Sherlock pursed his lips, nodded, and ran off to fetch Mummy's blanket. It was smaller than Cook's duvet, and much prettier anyway. It was made of many small pieces of different sizes and looked like a mostly-pink rainbow had exploded all over Mummy's bed. It was a great blanket.
It was also heavy. Sherlock pulled it with both hands, but it still took him a long time to drag it all the way to the library.
"There," he said proudly.
John looked at Mummy's blanket, and at his own chocolate-stained fingers, and at Mummy's blanket again, vaguely horrified.
"It's too pretty!" He said it firmly, but still a bit like an apology, like he knew Sherlock was working hard and he was being a bit ungrateful, so Sherlock did something he'd never done before: he forgave him.
"Stay," he said again.
He knew the perfect blanket for getting chocolate all over, but when he brought it from Mycroft's bed, John looked sad again and said that it was "too thin!"
By this point, Sherlock had figured out that a sad John, with his wobbling lower lip and his wide eyes and his stoic refusal to cry, was a curiously difficult thing to look at, so he quickly turned and ran away.
When he came back with Effie-the-maid's blanket, John thought it had "too many flowers." Daddy's blanket was "too old," the throw blanket from the sitting room was "too itchy," and Sherlock's own blanket, offered in a last-ditch effort, was "too the wong colour."
Sherlock glared at John. Really, must he be so difficult? The stupid blanket was so stupid, Sherlock didn't even remember what colour it was! John should just pick one from the heap around him and shut up!
"You're abomimble," he said in disgust.
John crossed his arms and glared right back. Sherlock blinked. Why was his heart skippiting so oddly?
"A proper blanket's orange," John said firmly, the authority of all things good and proper.
Sherlock rolled his eyes. Why hadn't John said so in the first place? This could have been solved ages ago!
"I've an owange bwanket," he told John. "Come."
He pulled at John's hand until John got up. It made his own fingers all chocolate-y too, but he didn't care. He dragged John out of the library and through the halls and corridors back to his room, where he closed the door behind them so no one would ask what they were doing. Then he crawled into the secret space under his bed.
The orange blanket lay crumbled where he'd stuffed it after the doctor-lady had given it to him. That had been the day Daddy had Gone Away and Sherlock barely remembered any of it, but he did remember the doctor-lady's insistence that Sherlock should take the blanket because he was In Shock and the blanket was supposed to make him Not In Shock. He didn't think it had helped all that much, but he'd kept it anyway.
"Owange," he said, and handed it to John with the satisfaction of a thing done well, like when he did his letters.
John curled his fingers into the blanket and beamed at Sherlock in a way that made Sherlock's heart do that odd skippity-thing again.
"Tha's amazing!" he declared, and then he leaned forward and bumped his lips against Sherlock's and ran away and Sherlock felt his cheeks heat up and his lips tingle and his heart pound like mad and decided that maybe, just maybe, blankets weren't so stupid after all.
And maybe John was a bit important as well.