

March 6, 1971
2h 30m
EN
Timothy Combe
Professor Emil Keller has created a machine that can pacify even the most dangerous of criminals. But when the Doctor and Jo arrive at Stangmoor Prison for a demonstration, things start to go horribly wrong - especially when they discover that the Doctor's old enemy the Master is responsible for the machine.

Jon Pertwee
The Doctor

Katy Manning
Jo Grant

Nicholas Courtney
Brigadier Lethbridge-Stewart

Richard Franklin
Captain Mike Yates


Don Houghton
11

John Levene
Sergeant Benton

Roger Delgado
The Master

Pik-Sen Lim
Captain Chin Lee

Raymond Westwell
Prison Governor

Michael Sheard
Dr. Roland Summers

Simon Lack
Professor Kettering

BBC
GB