As Wilbur explores her life, she finds she was raised by a very strict fundamentalist Christian minister and his paranoid schizophrenic wife in a small town. Her father attempted to ignore it, as did the local pediatrician. Her father did not believe either Sybil or her mother was ill.
She was emotionally, sexually and physically abused by a mother who was convinced in her paranoia that she was sending her to heaven. She used an enema to force water into her and then forced her to "hold" it. She inserted knives, button hooks, etc., into her vagina. She called to her to come for affection, then kicked her down the stairs. She locked her in a wheat bin in the barn and left her for dead.
Sybil ends up spending years in therapy with Dr. Wilbur, a psychoanalytic psychotherapist, who uses mind-altering drugs, hypnosis and dream analysis to uncover her Multiple Personality Disorder . She has tens of personalities, from little boys to adult women of greater and lesser ability to function. Various personalities come and go, each with his/her own talents and abilities, to get her through difficult situations. The most competent is Vicky, who speaks with a French accent. Sybil, the executive personality, is not fully aware of the "others. So she is often confused and loses blocks of unaccounted-for time. Wilbur regresses her through hypnosis to get her to remember and confront the abuse. She traveled to Sybil's home town to find the purple crayon scratches made when Sybil was left for dead. Through Wilbur's psychotherapy she is able to "integrate" and eventually become a college professor of art She and Wilbur remained friends.