Doctor Who (1963) Season 8 Episode 8 The Mind of Evil (4)

The Doctor and Jo find themselves inexplicably transported to Stangmoor prison, where a demonically possessed prisoner is about to be executed. As they investigate, they discover that the prison is the site of a top-secret UNIT operation, and that the Master is behind it all. Meanwhile, the Doctor's old nemesis is working on a device capable of sucking the negative emotions out of the world's leaders, leaving them vulnerable to suggestion. Can the Doctor stop the plan before it's too late, or will the Master finally triumph? As the tension rises, the Doctor's companions find themselves drawn into the perilous situation, each with their own part to play in the ultimate battle between good and evil. With heart-stopping action, thrills, and unexpected twists, "The Mind of Evil" is a classic episode of this beloved sci-fi series.