Nora Goodrich (Brenda Marshall) is a dedicated research scientist who is very close to a breakthrough in her field of anesthetics. She allows herself to be used as the subject of an experiment, and becomes the victim of sabotage by her jealous assistant (Hillary Brooke), who is her rival for the affections of the same man (William Gargan).
Nora is scarred by the accident, but fate takes a hand when a vicious blackmailer (Ruth Ford), part of an extortion scam that was being worked on her, breaks in to her apartment. In the ensuing struggle, the lady grifter is killed and then mistaken for Nora, while the real Nora goes into hiding.
Taking the identity of the dead woman, she realizes how she has been betrayed and maimed and plots an elaborate revenge, undergoing reconstructive surgery that changes her whole appearance. She then reintroduces herself into the lives of her former associates, in her new guise, and begins her revenge.
Before her plans can be concluded, however, her masquerade backfires on her, when she finds herself accused by the police -- of the murder of Nora Goodrich.