Katy Manning

The Master is behind the Keller Machine and uses it to recruit the rioting inmates at Stangmoor Prison. He plans to capture a missile and fire it at the World Peace Conference.

The Doctor is desperate to save the lives of Jo and everyone trapped inside the Miniscope, but is hindered by the Inter Minorans who have their own agenda.

A full scale riot takes place at the Prison and Jo is taken hostage. Meanwhile, at the World Peace conference, the Chinese delegate's aid prepares to kill the American delegate.

The Master forms an uneasy alliance with the Doctor so that between them they can subdue the Keller Machine which is now out of control.

The Keller Machine breaks free of the Doctor's restraining device and the Doctor has no choice but to turn the parasite against the Master.

The Doctor and Jo land on a spaceship in the far future as it is attacked by Ogrons, which the human crew see as Draconians. The Doctor and Jo are taken to Earth as spies.