 It is the first of three episodes that form a linked narrative, followed by "The Sound of Drums" and "Last of the Time Lords".The episode serves to re-introduce the Master (John Simm), an alien villain of the show's original run who previously appeared in the 1996 television movie "Doctor Who".Set close to the end of the universe 100 trillion years in the future, the episode involves Professor Yana (Derek Jacobi) attempting to send the last of humanity in a rocket to a place called "Utopia".