A dangerous adventure begins for the Doctor and Jo Grant when they visit Stangmoor Prison for a demonstration of the new Keller Machine. The device is said to extract negative emotions from convicted prisoners, leaving them pacified and reformed. But when it apparently goes wrong, a far more sinister purpose is revealed
The Doctor's old enemy, the Master, is behind the machine, working in conjunction with an alien mind parasite. As unrest builds amongst Stangmoor's prisoners, the Master takes control, his ultimate aim to hijack a deadly missile and threaten the World Peace Conference taking place in London. As Brigadier Lethbridge-Stewart leads UNIT in the defense of both the missile and Stangmoor, the Doctor and Jo must fight to stay alive and help avert a third world war!
A dangerous adventure begins for the Doctor and Jo Grant when they visit Stangmoor Prison for a demonstration of the new Keller Machine. The device is said to extract negative emotions from convicted prisoners, leaving them pacified and reformed. But when it apparently goes wrong, a far more sinister purpose is revealed
The Doctor's old enemy, the Master, is behind the machine, working in conjunction with an alien mind parasite. As unrest builds amongst Stangmoor's prisoners, the Master takes control, his ultimate aim to hijack a deadly missile and threaten the World Peace Conference taking place in London. As Brigadier Lethbridge-Stewart leads UNIT in the defense of both the missile and Stangmoor, the Doctor and Jo must fight to stay alive and help avert a third world war!