 At the start of the episode the Earth is teleported out of its spatial location shortly after the Doctor and Donna arrive to investigate Rose Tyler 's warning at the end of " Turn Left " . The Doctor contacts the Shadow Proclamation , a universal police force , to find Earth . They determine twenty @-@ seven missing worlds — including Earth , Adipose III , Pyrovillia , and the Lost Moon of Poosh — automatically reorganise into a specific pattern when placed near each other . Donna mentions the disappearance of bees on contemporary Earth ; this allows the Doctor to trace the planets to the Medusa Cascade , an inter @-@ universal rift . 
