Clementine has spent her whole life hearing about the Doctor. Without a moments hesitation she would jump into that big blue box and fly away with him.
Thats what she thought.
When she bumps into him in a seemingly bizarre way she thought she was going crazy. The sheer insanity of this was mind blowing but Clementine managed to keep her head. She's whisked away by a seemingly reluctant Doctor, he was the seeming shadow of the legend she thought he was. Instead of going to ancient Rome they end up someone entirely different and seemingly sinister.
The Doctor discovers finally once and for all, the secret of the Weeping Angels. It was everything he didn't expect.