The prompt for this one was "The Doctor turns up at odd times in Sherlock's life"…It sort of turned out to be more that The Doctor turns up…The situations might become more odd, but the first couple are pretty standard…
House Calls: Part One
Sherlock is four when he first sees the blue box. He doesn't know what it is, but knows that it shouldn't be in the hallway at night.
Being a more composed child than most his first reaction on finding it, after reading it's "Police Box" sign, was not to scream and yell for help.
It was to knock.
And a man wearing a leather jacket and a stern expression opened the door quickly. His face changed however into what he clearly hoped was a winning smile as his eyes fell on the child stood before him.
"Hello mate, could you do me a favour and tell me where I am?"
Sherlock scowled, and the mans smile wavered a second.
"On the third floor of Finchback Manor, on the Holmes estate."
The man waited, his smile becoming a puzzled frown.
"Thanks." he said, glancing again at the hallway around him, "Not where I expected, but ah, yes. Well little chap, goodbye!"
And the man snapped the door shut sharply and Sherlock began to walk away. Until he heard the door open again.
"Just out of interest," said the man, poking his head out of the door, "what's your name?"
Sherlock looked at the man levelly. He had no reason not to tell him. His rudimentary logic told him that if he was in the house he could be trusted. Like mother, or Mycroft.
"Sherlock Holmes."
"Well Sherlock Holmes, nice name by the way, I'll be seeing you very soon."
He gave Sherlock a cheeky wink and promptly shut the door again.
It was a moment before the blue police box began to make the most incredible noise, and to fade in and out of sight, before disappearing completely.
Sherlock still had his mouth gaping when Mycroft came to see what the noise was. He carried a tired Sherlock back to bed, unbelieving of the crazy story his little brothers sleep-addled brain had produced.
Sherlock was asleep moments after Mycroft had gone. By morning he had slept away any memory of the big blue box.