Attempting to return to UNIT HQ, the Doctor and Sarah land in England in 1911, in the Scarman family home, occupying the future site of UNIT HQ. Here an ancient force is preparing to return and wreak destruction on the Universe. Sutekh the Destroyer, last of the Osirans, has posses Egyptologist Marcus Scarman and 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 could stand against him.