The Doctor Who television show features the Doctor and companions traveling through time and space in the TARDIS to entertain audiences aged 11 and up. In this episode, genre codes include the Master hearing drumming in his head foreshadowing his regeneration, and humans evolving to appear alien. The characters include the Doctor, companion Martha Jones, and immortal ally Captain Jack. Key events involve the Doctor discovering another surviving Time Lord, the Master, who tricks him by becoming president in the 21st century. The narrative follows the characters in conversation as the story progresses through a futuristic version of the 21st century depicting a quest for a perfect world.