As Stalin's chief of secret police, Lavrenti Beria was the most feared man in the Soviet Union, with a reputation for cruelty. Like Stalin, Beria came from a poor peasant village in Georgia, and his working life was devoted to making real Stalin's vision of a strong Soviet state. Forty years after his death, extensive new research has uncovered an even more complex and horrifying picture of a man who manipulated and murdered his way to the top. Beria's relationship with Stalin was the key to his success, and ultimately his undoing, as former colleagues and victims reveal for the first time on television in the last in the series.