In 1977, a serial rapist struck Ohio State University. Overwhelming evidence quickly led investigators to Billy Milligan, an aimless young man with a traumatic childhood and a criminal record. Yet upon his arrest, Billy had no memory of the assaults, and his mannerisms seemed to change on the spot. A parade of psychiatrists diagnosed him with multiple personality disorder (now known as dissociative identity disorder), eventually determining that as many as 24 distinct "multiples" existed within his mind. In a case that captivated the nation, their analysis anchored a first-of-its-kind legal defense strategy, and Billy was found innocent by reason of insanity. His trials, however, were far from over. Director Olivier Megaton (Taken 2) brings his feature film sensibility to this gripping investigative series, setting up cinematic interviews with the Milligan family, as well as friends, doctors, and the law enforcement professionals who've tried to untangle the truth. Over 40 years since the landmark verdict, nearly everyone is still asking questions: Were Billy's multiple personalities indeed controlling his actions, or were they a convenient cover for a brilliant narcissistic sociopath? To what extent should charismatic criminals benefit from their notoriety? And were Billy's most violent crimes still to come?