The Doctor takes Rose home but they appear a year after they originally left by mistake. Rose's mother has been frantic and we learn that Mickey, her boyfriend, has been questioned in the matter of Rose's disappearance several times. A spaceship crash-lands in the Thames and the Prime Minister is nowhere to be seen. The next in command takes over but he and his confidants are not what they seem. The Doctor investigates the alien survivor of the crash to find that it is a super evolved pig, perhaps as a sort of joke. The Doctor and Rose go to Downing Street and discover that the Slytheen have taken over.