"New Earth" is the first episode of the second series of the British science fiction television series Doctor Who. It was first broadcast on BBC One on 15 April 2006. The episode is set five billion years in the future on New Earth, a planet humanity settled on following the destruction of the Earth in the 2005 episode "The End of the World". In the episode, the alien time traveller the Tenth Doctor (David Tennant), his travelling companion Rose Tyler (Billie Piper), and their old enemy Lady Cassandra (Zoë Wanamaker) uncover many artificially-grown humans having been infected with every disease in a hospital by a group of humanoid cat nuns as a way of finding cures for the diseases.