Terra is dying, when a strange man in a blue box comes to comfort her. One moment she has no idea who he is, and the next she remembers - she's known the Doctor her whole life. And he's going to make sure she's never alone.
She's brought up in a normal family, on a normal street, in a normal house, with a normal life.
The thing is no one told her what normal really was. And that's when she found out.
She was never normal after all.