Pinky (Jeanne Crain), a black woman who works as a nurse in Boston, finds she is able to pass for white. Afraid her true heritage will be discovered, she leaves her white fiancé (William Lundigan) and returns home to Mississippi. There, she helps her ailing grandmother (Ethel Waters) by caring for her employer (Ethel Barrymore), an imperious plantation owner. When she names Pinky heiress to her estate, the community rises in resentment, triggering a sensational court trial.