Attempting to return to UNIT HQ, the Doctor (Tom Baker) and Sarah land in England in 1911, where an ancient force is preparing to return and wreak destruction on the Universe. Sutekh the Destroyer, last of the Osirans, is planning to free himself from his prison on Mars. His robot Mummies are building a rocket to destroy the device which holds him prisoner and If he isn't stopped, there is not a force in the Universe which can stand against him.

All ten episodes of the 1980 revised version of the 1970s cult classic science fiction series. The series follows brother and sister Dan and Helen (Stephen Garlick and Sylvestra Le Touzel) who find and make friends with an alien who they call Peep-Peep (Colin Mayes). The episodes are: 'The Meteorite', 'The Spinning Compass', 'The Man in the Sandpit', 'In Danger!', 'The Hold-Up', 'Where Is Tom?', 'The Hunt for the Car', 'The Lake', 'Captured!' and 'In the Spaceship'.