Summary: The first episode examines the start of the Unabomber's campaign of terror spanning from 1978 to 1985, and dives into Kaczynski’s childhood to discover what might have made a young mathematical genius with few friends evolve into a sociopathic terrorist.

Summary: Picking up in 1985, Part Two tells the story of how the Unabomber began to ramp-up his terror campaign, claiming his first murder and taunting his FBI pursuers. Kaczynski’s secret journals from his time as a grad student in Michigan reveal the extraordinary moment when his thoughts first turned to murder.

Summary: Part Three recounts the period from 1993 to 1996, when the Unabomber was holding America ransom with a series of increasingly powerful bombs before his arrest in 1996. Kaczynski's brother and sister-in-law reveal the emotional story of how they came to suspect he was the Unabomber, which ultimately led to his arrest.

Summary: The final episode of the series examines Kaczynski's trial, with the revelation that he was subjected to a secret psychological experiment as a teenaged student at Harvard, a fact some claim could have been responsible for turning him into the terrorist he became.