Doctor Who/The Mind of Evil

The Mind of Evil
Season 8, Episode 2
Airdate	January 30, 1971
Production Number	FFF
Written by	Don Houghton
Directed by	Timothy Combe
← 8x01 Terror of the Autons	8x03 → The Claws of Axos
Doctor Who — Season Eight

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The Mind of Evil is the second serial of the eighth season of Doctor Who, and the fifty-sixth serial overall.

Guest Stars: Neil McCarthy (Barnham), Roger Delgado (The Master (Professor Keller), William Marlowe (Mailer), Pik-Sen Lim (Chin Lee), Michael Sheard (Dr. Summers), Fernanda Marlowe (Corporal Bell), Dave Carter (Prison Officer), Hayden Jones (Vosper), Tommy Duggan (Senator Alcott), Eric Mason (Senior Prison Officer Green), Simon Lack (Professor Kettering), Roy Purcell (Chief Prison Officer Powers), Kristopher Kum (Fu Peng)

Plot Overview

The Doctor and Jo arrive at Stangmoor Prison for a demonstration of the Keller Machine, a device capable of extracting negative emotions from criminal minds. A prison riot puts Jo in danger while the Doctor assists the Brigadier. Meanwhile, at the World Peace Conference, the Chinese delegate's aid prepares to kill the American delegate. Newly recovered, the Doctor escapes from his cell with Jo. The Master plans to use the Keller Machine to recruit the rioting inmates at Stangmoor Prison and attack the World Peace Conference. The mind parasite within the Keller Machine becomes too powerful for the Master to control. It learns how to move on its own and goes on the hunt for new minds. 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 Brigadier brings the prison under control, but the Master has escaped and plans to start a world war. 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.