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 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 Interplanetary Mining Corporation, represented by Captain Dent, arrives on the planet claiming that the colonists have no right to be there.

The Master arrives, posing as an adjudicator from Earth who has come to settle the dispute between the colonists and the miners. However, the Master has an agenda of his own.

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.