What Ever Happened To Christina?

"'What Ever Happened To Christina?'" is the fifth episode of the tenth season of Doctor Who, where the Doctor is preyed on by a time vampire when he believes Christina to have been killed.

Synopsis
"Your TARDIS will be mine, Doctor. One way or another!" - Time Vampire

The Doctor and Christina arrive on Earth on the trace of a distress call, but when they arrive Christina is seemingly killed in a car accident. Is she really dead? Or is their something far worse at work?