Sybil Dorsett [Sally Field] is a teacher who suffers a sudden breakdown in front of her students, and she is subjected to a neurological examination by Dr. Cornelia Wilbur [Joanne Woodward], a psychiatrist who suspects the episodes arise from a deeper, unaddressed problem rather than a simple medical issue. Sybil admits to blackouts and fears they’re intensifying, and Wilbur suggests the possibility of underlying trauma and a need for ongoing therapy. Sybil agrees to return, though she says she’ll have to ask her father before committing to more sessions.
Sybil’s father, Willard Dorsett [William Prince], and her stepmother, Frieda Dorsett [Jane Hoffman], are visiting New York. At a cafeteria lunch, Sybil explains that the problems from her childhood have resurfaced and that she wants to see Dr. Wilbur again. Her father makes it clear that they disapprove of psychiatry, a stance that both unsettles and destabilizes Sybil. In a heated moment, she dissociates into Peggy, an angry personality who shatters a glass in a fit of rage. That night, Dr. Wilbur receives a late-night call from someone identifying herself as Vickie, claiming that Sybil is about to jump from a hotel window. Wilbur rushes to intervene and rescues Sybil, who denies knowing Vickie. Suddenly, Sybil becomes hysterical and begins speaking as a young girl, introducing herself as Peggy, and Wilbur realizes she is dealing with a case of multiple personalities—as now understood, dissociative identity disorder.
In the following sessions, Vickie appears and reveals that she knows a great deal about the other personalities. She also introduces Wilbur to others, including Marcia, who is suicidal, and Vanessa, who plays the piano even though Sybil claims she has forgotten how to play. Over the weeks, each personality makes a distinct entrance in Wilbur’s sessions, and the details multiply: Vanessa even seems to fall in love with a neighbor named Richard [Brad Davis].
Wilbur begins to explain the structure of Sybil’s fractured psyche to her, and to prove the reality of the other selves, she plays back a session tape that captures their voices. Yet a voice that sounds like Sybil’s mother Hattie speaks, and the infant personality Ruthie emerges. The pre-verbal Ruthie cannot be communicated with yet, and Wilbur must wait for Sybil to return.
Life grows increasingly chaotic as the other personalities take on stronger presences. The group even sends a Christmas card to Wilbur, but Sybil—often in a purple hue—terrifies Peggy, who fears that purple color. Wilbur hypnotizes Vickie and asks about the purple memory. Vickie recounts a moment from Sybil’s childhood: her mother locked young Sybil in the wheat bin in the barn, and in an act of protest, Sybil used a purple crayon to scratch the inside of the bin so someone would know she had been there.
During a Christmas dinner, Vanessa invites Richard and his son Matthew [Tommy Crebbs] to join them, and Richard ends up spending the night in Sybil’s apartment. A nightmare wakes Sybil and she reappears as Marcia, who attempts to throw herself from the roof. Richard rescues her and calls Wilbur, but he soon moves away, a blow that deeply affects both Sybil and Vanessa. Confronted with her diagnosis once again, Sybil tries to convince Wilbur that she has been faking the other personalities and denies their existence.
Willard seeks out Sybil’s father again, and he reveals that Sybil’s mother Hattie [Martine Bartlett] was diagnosed with paranoid schizophrenia—though he denies any abuse toward Sybil. Wilbur also speaks with Sybil’s pediatrician, who provides a troubling account of internal scarring found during treatment for a bladder problem. Finally, Wilbur returns to the old Dorsett house and finds the green kitchen described by Sybil’s other selves, as well as the purple scratches inside the wheat bin. She brings these memories back to New York to show they really happened.
A drive with Wilbur yields a crucial breakthrough: Peggy reveals the horrific abuse she suffered at her mother’s hands. After Peggy tires, Sybil emerges and can finally express the rage she has harbored.
Wilbur hypnotizes Sybil to reintroduce the other personalities, and the moment comes when Peggy appears as a young girl. To everyone’s surprise, Sybil embraces Peggy, rather than fearing her, and the two form a tentative bond. A voiceover from Wilbur explains that, following this breakthrough, Sybil recovered her memories and went on to live a full and happy life as an academic.
- - -
Note: Cast references used in this summary include first-time mentions with actor-linked names: Sybil Dorsett Sally Field, Dr. Cornelia Wilbur Joanne Woodward, Willard Dorsett William Prince, Frieda Dorsett Jane Hoffman, Richard Brad Davis, Cam Camila Ashland, Dr. Castle Paul Tulley, Hattie Martine Bartlett, Matthew Tommy Crebbs, Grandma Dorsett Jessamine Milner, Dr. Lazarus Gina Petrushka, Dr. Quinoness Charles Lane, and Danny Harold Pruett.
