The Doctor encounters the first human colony on Mars, Bowie Base One.

When TARDIS explores an abandoned space station they find the last survivors of Earth.

An insect life form has laid eggs that infect one of the re-animated human beings.

The Doctor and friends attempt to lure the Wirrn hatchlings towards a shuttlecraft.

Although fully changed into a Wirrn, the human in Noah tries desperately to break through.

The TARDIS arrives in the future on the planet Pluto where there are now six suns, a breathable atmosphere and a large industrial community. The Company controls the planet and exploits the workers, pays them a pittance and then taxes them on everything imaginable. The Doctor and Leela join forces with an underground band of rebels led by a man named Mandrel.

As plague sweeps the country, the Doctor discovers a more exotic threat at work - shipwrecked Terileptil convicts, intent on making the planet their own.

England, 1925. A case of mistaken identity leads to the TARDIS crew attending a cricket match and masked ball at stately Cranleigh Hall. There is a mysterious deformed maniac in the attic.