S8, E5: At Stangmoor Prison, the Doctor and Jo watch a demonstration of the Keller Machine which can extract evil impulses from criminals. But the experiment goes wrong and a man dies.

Starring Pik-Sen Lim, Raymond Westwell, Michael Sheard

S8, E5: At Stangmoor Prison, the Doctor and Jo watch a demonstration of the Keller Machine which can extract evil impulses from criminals. But the experiment goes wrong and a man dies.