The Doctor and his companions arrive in a London very different from what they remember.
The Doctor and Ian are captured and taken to the Dalek ship.
Hiding on board the Dalek spaceship, Ian is taken to the mines of Bedfordshire.
The Doctor, Susan and David discover a nearby firebomb, left by Robomen to destroy London.
Ian and his friend Larry are chased by the Slyther, protecting the Bedfordshire mines.
Barbara realises how to control the Robomen and orders an attack on the Daleks.
