I'll be honest. I have yet to discover a Dr. Who fanfiction that I actually enjoyed reading. This is the beginning part of my own Dr. Who fanfiction that will probably be no better.
The Doctor stared at a small, blinking light on the TARDIS console. "Impossible," he whispered, his already high eyebrows rising.
"Nothing is impossible, only highly improbable. You taught me that, Doctor," said Clara Oswald, absentmindedly, keeping her eyes glued to a book. "I mean, simultaneous time and space travel is thought to be impossible, but here I am, standing in a machine, that literally is an acronym for 'Time And Relative Dimensions Into Space–"
"Shh!" The Doctor whispered. He gingerly touched the blinking dome.
Clara looked over at the Doctor. "What? What is it?" She asked as the Doctor rushed over to the monitor. "A sign," whispered the Doctor. "Of..." Clara prompted.
"Another Timelord. On Earth." Clara's eyes widened. Millions of miles away, a girl was awakened by a malfunctioning alarm clock, unaware of the adventure she was getting up to.