The Time Lords takes control of the TARDIS and the Doctor and Jo arrive on a Earth Colony in the 25th Century, where a ruthless mining company are using a dinosaur-like creature to force the colonists to leave the planet. Where the Doctor and Jo learn that The Master is on the planet and is in search of a doomsday weapon that is hidden somewhere on the planet.

The Doctor makes it back to the colony and warns Ashe what Dent is up to but when Jo and Winton try to find proof they are captured.