While an exhausted Doctor falls asleep, a robot steals blueprints for a disintegrator gun.

The Doctor helps the Brigadier investigate the culprit behind a series of crimes.

The Doctor and Sarah realize that Hilda Winters, a director for Think Tank, programmed the robot that stole a disintegrator gun. The organization planned to start a nuclear war, eventually win and rule the world.

While Think Tank hides in a bunker waiting for the nuclear holocaust to begin, the Doctor is in a frantic effort to stop the organization from achieving their goal of world domination.

The Doctor tries to outwit Ice Warriors.

The Doctor races to save Earth.

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.

In the Crimean War, the Doctor discovers the British army fighting a brutal alien army of Sontarans, as Yaz and Dan are thrown deeper into a battle for survival.

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.

Harry and Sarah walk into a trap while the Doctor solves a mystery.

Harry and Sarah walk into a trap while the Doctor solves a mystery.

The Doctor and friends discover a plot to destroy the newest moon of Jupiter.

The Cybermen want to destroy Voga because it's made of a substance that can kill them.

A sinister landlord shows Bill and her friends a "perfect" house to share.

The Doctor returns to the Ark to recover the Tardis, but things have changed.