4.6 - The Doctor's Daughter

From IMDB:
The TARDIS as seen before seems to display a mind of Its own and whisks the Doctor, Donna and the Time Lords former companion Martha Jones to the planet Messaline, a world where a savage war is being fought between humans and a race of fish like creatures called the Hath. In the ensuring confusion of their arrival, Martha is abducted by the Hath. Rescuing Martha becomes the Doctor and Donna's main priority as well as attempting to put a stop to the ugly war that has consumed the planet. But that would have been complicated enough had it not been for the fact that the Doctor had suddenly been made a father again.

26 out of 93 (28.0%) raters say this story requires a previous story.