Family Christmas

The Doctor glanced up from under the console when he heard a knock on the TARDIS door. He was sure no one knew where he had parked the TARDIS, and he was positive it wasn't one of the companions, they all had keys and River just let herself in. He sighed as he climbed back up to the top half of the console room and over to the door. He opened it and discovered a young teenage boy with shaggy black hair outside his door. "Can I help you?" the Doctor asked. "Yes, are you Doctor John Lungbarrow Smith?" "I am, who`s asking?"  "I am, sir, see I have an invitation for you from a Ms Noble."