Synopsis: The TARDIS lands on the planet Demeter where the travellers are taken to be an invasion force from the neighbouring planet, Bellus. Shortly after the misunderstanding is cleared up the real attack from Bellus takes place, with vibrations shaking Demeter, causing mass destruction.
Synopsis: The Doctor, John and Gillian land on the planet Go-Ray where the entire planet is powered by Cardium. As the doctor and his grandchildren approach the Cardium HQ an explosion takes place causing the power supply to fail. The travellers are blamed by strange, wheeled Go-Rays who imprison them.
Synopsis: After colliding with an exploding galaxy, the TARDIS takes the Doctor to England in the year 5000. There, in the ruins of the British Library, the Doctor meets the last remaining men, or 'norms', on Earth. The TARDIS is carried off by a giant airship piloted by a race of mute supermen known as the 'mutants'. Defeating the leader of the mutants the Doctor saves the TARDIS from destruction. With the norm, Brod, the Doctor travels to New York in 1872. There they seek out Professor Cassells whose biological experiments were the original cause of the Earth's devastation in the future. However, unable to believe the Doctor's incredible story, the Professor refuses to halt his research.