Sherlock slammed the door on his parents arguing and stormed out into the wide, overgrown garden. Not looking back, he wove his way through the thickets of bushes in the old family home, never receiving a scratch, until he reached a small enclave surrounded by tall trees and overshadowed by a weeping willow, blocking out the outside world. Not even Mycroft would find him here, even if he could find the energy.

The twelve-year-old ran his fingers through his dark hair, making it even messier than usual, and let out a frustrated yell. Mama and Papa argued often, and loud, and, Sherlock thought, for no clear reason. He wanted to tell Mama that Mycroft and him being "abnormal" wasn't a bad thing, and Papa that he had to stop being so jealous. They didn't make sense.

Sherlock leaned against the wide trunk of the willow tree, and picked absent-mindedly at the scabs on his knees. Inside, there were always new people, changing people, things moving, and it crowded his senses until it became hard to think, even without all the stuff he was "supposed" to remember. Like that mattered. But here, in the shady glade, all was quiet and still.

Until, all of a sudden, it wasn't.

A deafening rasping noise that sounded like someone ripping open the air- which wasn't that far off the truth- echoed around the clearing. Sherlock stumbled to his feet, and pulled out the flip knife he always kept in his pocket without so much as batting an eyelid. An old-fashioned 1950s police telephone box, about seven feet tall and royal blue in colour, slowly throbbed into being as dead leaves whirled around it.

"Impossible," Sherlock muttered, grey eyes fixed on the box, "or maybe… just really, really improbable."

The noise stopped, the door swung open and a man in a tweed jacket and red bowtie tripped on his own feet and fell out, the door slamming shut before Sherlock could see what was inside. The man had had something in his hands, but as he fell he had dropped it and it rolled down to Sherlock's feet- a skull. He picked it up, and examined it.

"Three to four years old, cleaned in some sort of acid and bleached." Sherlock announced, to the air at large. The stranger picked himself up, pushing his floppy black hair out of his eyes, straightened his bowtie and grinned. Sherlock flicked his attention up to the stranger, before returning to his new subject.

"Cleaning of the skull is what would normally happen in most scientific exhibits, but the bleaching suggests a more aesthetic use. They used to do this sort of thing in the theatre, before someone figured out how to make a model skull, and this technique became obsolete." Sherlock's eyebrows furrowed. "My name's Sherlock Holmes- who are you?" he shot at the stranger, who was still wearing a smile like a deranged banana.

"I'm the Doctor."

"Not your real name, obviously. How did you get here? How does your ship travel? Why does it look like that?"

The Doctor rubbed his forehead with the palm of his hand. "I'm not sure, I was having a drink with some friends and we got into an argument about who that-" he waved at the skull "-was, and then I offered to go and check, because I thought, when you get an object to cross its own timeline there's normally some sort of sign, so I could just whack who I thought it belonged to around the head twenty years ago and see if there was an explosion, and I obviously got the dates wrong. Oh, and the ship's called the TARDIS, she travels in a very complicated way that would take at least two hours and a chalkboard to explain, and she looks like that because the chameleon circuit broke." As he said all of this, the Doctor paced up and down, waving his hands and spinning occasionally. Sherlock, by contrast, was barely even blinking.

"So you're a time traveller then?" he asked.

The Doctor froze. "Of course not, that would be impossible."

"All the evidence points to you being one. And if you ignore the usual laws of physics that we are aware of at this point in time, it seems a lot more possible than every other explanation."

The Doctor rubbed his hands together. "You don't have many friends, do you?"

Sherlock shrugged his shoulders. "Don't need them."

The Doctor, although quite a young man, suddenly seemed over a thousand years old as Sherlock said that. Storms raged in his eyes, and then suddenly cleared as he strolled towards the boy and kneeled down so he was at eye level. "Oh, everybody needs friends. Even geniuses like us."

"You don't seem like a genius."

"Well, that's 'cause you haven't seen me do anything clever yet!" the Doctor frowned like a seven year old who had just had his sweets taken away from him. "Well, I don't suppose I could go back to Will and the boys now, or I'll never live it down. But I can't really have another skull lying round the place. I have too many skulls."

"I'll look after it for you," said Sherlock quickly.

"Well, that's very nice of you!"

"If you tell me whose skull you think it was."

"Well, we'll never know that now, will we?"

"Because you're too cowardly to lose a bet and tell your friends that you got very badly lost in time."

"Yes," said the Doctor, acting nettled, "that." Sherlock laughed.

"Can you at least tell me what it was being used for?"

"Fine." The Doctor picked up the skull, took a few steps back, cleared his throat and announced:

"Alas, poor Yorick!"

Sherlock stared at him blankly.

"Oh, come on!" exclaimed the Doctor. "My acting isn't that bad! You know, Hamlet? William Shakespeare?"

"Oh, that guy."

"That guy?!"

"He was never very important to me, so I forgot him," Sherlock pointed out. "So is that what the skull is meant for, then?"

"Was meant for, yeah."

"Okay, give it to me then." Sherlock held out his hand, but the Doctor held back, frowning at him.

"If I give this to you…" The time traveller said slowly.

"Yeah?"

"Then it's got to be your friend."

"I beg your pardon?"

"Friend! Remember, you said you didn't have any? Well, now you do!"

"You have got to be kidding me," Sherlock snorted.

"No, my jokes are normally much worse than that. Listen." The Doctor rested his hands on the boy's skinny shoulders. "One day, you will become very, very successful, Sherlock Holmes. You will have the world in your grasp, even when it seems you have nothing. And you will have a friend who is worth more to you than any of that. Trust me, I'm a time-travelling Doctor, I know these things. But until then, you're gonna need another friend. Look after him for me, okay? Don't make the mistakes I do."

The Doctor smiled sadly to himself, and Sherlock wondered where all his friends were- his proper ones, that is, not those who he would never talk to again after losing a bet. Sherlock got the impression it would take a lot more than that to keep the Doctor's true friends from him.

"Keep safe, kiddo." The Doctor patted him on the head, spun around one last time and walked away to his blue box. As he went to close the door behind him- being careful not to show what it looked like inside- Sherlock called after him.

"Doctor?"

"Sherlock?"

"I hope you find a new friend, too."

"I'm sure I will, Sherlock Holmes." And with that weird, rasping noise, the TARDIS faded away into nothing, leaving a twelve year old genius and a skull alone in the clearing.

A/N So I said on tumblr that I would write this, the idea was suggested by somebody else (sorry but cannot for the life of me remember who) and I have since had a couple of messages telling me to write it. So, yeah, I did. And now my other fics feel all neglected and sad. Oh well. Please review, favourite, show to your friends and so on, because everything likes that makes me yell rainbows. I hope you enjoyed it!