Trainee doctor Martha Jones has her hands full balancing her medical studies with placating her demanding family. So the last thing she needs is to find that the hospital where she works has been transported to the moon, where it's invaded by an overbearing alien police force. There she encounters a patient called John Smith, who seems curiously at ease with the situation…

Martha has to save her family from the lunatic schemes of the monstrous Professor Lazarus.

Harry Saxon becomes Prime Minister and his reign of terror begins – but that's only the start of his ambitions, as he announces mankind's first contact with an alien race, the Toclafane. An audacious plan spanning the whole of time and space begins to close around the Earth, in the penultimate episode of Russell T Davies's Doctor Who.

One year has passed since the events of "The Sound of Drums." The Earth has been conquered and its population enslaved, the Doctor is the Master's prisoner, and the warships of a new Time Lord Empire rise from the ashes. The fate of the world is in Martha Jones' hands.