STORY PLOTLINE
The Doctor and Jo visit Stangmoor Prison for a demonstration of the Keller Machine - a device claimed to be capable of extracting negative emotions from hardened criminals.
The Master uses the evil impulses stored within the Keller Machine - actually the container for an alien mind parasite - to cause unrest at Stangmoor. He then enlists the convicts' aid to hijack the Thunderbolt missile, planning to use it to blow up the peace conference and start World War Three.
DVD EXTRAS
COMMENT
