The Doctor and his companions are in the middle of nowhere in space where they receive an electronic box which has a message in it. The Doctor feels compelled to follow the message even if it takes him out of the universe to an asteroid.
On the asteroid, the Doctor meets people themselves the Auntie, Uncle and Nephew and one other. The Auntie and Uncle are human but the Nephew is an Ood. It later transpires that the humans are a patchwork of others, the Uncle has two left feet.
The Doctor sends Amy Pond and her husband Rory Williams back to the Tardis whilst he investigates the asteroid. The Doctor discovers that other Timelords had been lured to the planet and had been killed. The one other is a human, a youngish woman who becomes possessed with the spirit of the Tardis and starts communicating with the Doctor.
Once the companions are in the Tardis, the Tardis becomes possessed by the spirit of the asteroid. The spirit takes the Tardis off into space with the companions inside. The Doctor and the woman who calls herself Sexy after what the Doctor calls the Tardis build another Tardis to go after the blue telephone box.
Whilst onboard the Tardis, the companions are tricked and played with by the possessed Tardis. Sexy is able to communicate with Rory and advises him what to do. Rory obeys and the Doctor is able to land in the Tardis and take control. The spirit of the real Tardis leaves the body of Sexy and takes back control of the Police Box.