In 1951, Eve White is a timid, self-effacing wife and mother who has severe and blinding headaches and occasional blackouts. Eventually goes to see psychiatrist Dr. Luther, and while having a conversation, a “new personality”, the wild, fun-loving Eve Black, emerges. Eve Black knows everything about Eve White, but Eve White is unaware of Eve Black.
Eve White is sent to a hospital for observation after Eve Black is found strangling Eve White’s daughter, Bonnie. When Eve White is released, her husband Ralph finds a job in another state and leaves her in a boarding house, while Bonnie stays with Eve’s parents. When Ralph returns, he tells her that he doesn’t believe she has multiple personalities and tries to take her to Jacksonville, Florida, with him but she feels she isn’t well enough to leave and is afraid Eve Black will try to harm Bonnie again and refuses to go. Eve Black confronts Ralph at his motel where he not only realizes Eve Black is real, but also she convinces him to take her to Jacksonville. When Eve Black goes out dancing with another man, Ralph slaps her when she returns and ends up divorcing Eve White.
Dr. Luther considers both Eve White and Eve Black to be incomplete and inadequate personalities. The film depicts Dr. Luther’s attempts to understand and deal with these two faces of Eve. Under hypnosis at one session, a third personality emerges, the relatively stable Jane. Dr. Luther eventually prompts her to remember a traumatic event in Eve’s childhood. Her grandmother had died when she was six, and according to family custom, relatives were supposed to kiss the dead person at the viewing, making it easier for them to let go. While Eve screams, her mother forces her to kiss the corpse. Apparently, Eve’s terror led to create different personalities.
After discovering the trauma, Jane remembers her entire life. When Dr. Luther asks to speak with Eve White and Eve Black, Jane says they are gone. Jane marries a man named Earl whom she met when she was Jane and reunites with her daughter Bonnie.