As schoolgirl BFFs Donna and Natalie get reacquainted, a mysterious stranger dogs their steps. Is the Doctor keeping tabs on her, or is the truth far more sinister?
Donna and Nat have been stolen - along with the TARDIS - and they find themselves crash-landing on an alien world. On the planet Valdacki a very successful invasion is already underway. And it's one that has the very best PR.