Parts: 1 (60-minute)
Writers: Russell T Davies and Gareth Roberts
Airdate: 11 April 2009
Production Code: n/a

Doctor: tenth
Companion: Christina

Creature Feature: Tritovores, Stingrays

Story: The number 200 bus to Brixton is carrying a pair of unusual passengers - Lady Christina de Souza, a confident aristocrat who has just stolen a valuable exhibit from the International Gallery, and the Doctor, who is tracking a hole in reality. When the Doctor's tiny little hole turns into a giant wormhole, the bus drives straight through it and ends up on a desert planet, with no apparent means of returning home.

With Christina's help, the Doctor must figure out how to repair the bus, but time is not on their side. In the distance, a storm rages, coming ever closer to the crashed bus, and one of the passengers on the bus somehow knows that with the storm comes death for everyone. And another question looms large: what caused the hole in reality to appear, and why has it suddenly turned into an ever-enlarging wormhole? The answer spells disaster for the entire Earth...