Multiple Personality Disorder barely existed as a diagnosis before the 1980s, when tens of thousands of Americans were suddenly identified with it. The film traces the surge back to a single cultural event: the television film "Sybil," which dramatized one woman's case and turned MPD into a household term almost overnight. It then follows the unraveling, as Sybil's own diagnosis comes under challenge and psychiatrists split into opposing camps, some insisting the condition is real and rooted in severe childhood trauma, others arguing it was manufactured by suggestible patients and eager therapists. The disorder has since been renamed Dissociative Identity Disorder, a rebranding the film treats as evidence of how unsettled the science still is. Clinicians on both sides make their case directly to camera, describing how a new personality can supposedly form to absorb abuse the original self cannot bear, and how that same mechanism might instead be coached into existence. No verdict is handed down; the film leaves the diagnosis exactly as contested as it found it.