- Directors: Jacques Tourneur
- Producers: Val Lewton
- Writers: DeWitt Bodeen
- Genres: Drama, Fantasy, Horror, Romance, Thriller
- Actors: Simone Simon, Kent Smith, Tom Conway
At a city zoo, Serbian-born fashion designer Irena Dubrovna (Simone Simon) makes sketches of a black panther. She catches the attention of American naval construction designer Oliver Reed (Kent Smith). Irena eventually invites him to her apartment for tea. As they walk away, one of Irena’s discarded drafts is revealed as a panther impaled by a sword.
At her apartment, Oliver admires a statue, a crowned medieval figure on horseback impaling a cat with his sword. Irena informs Oliver that the figure is the (fictional) King John of Serbia and tells him a story. According to legend, a Satanic tribe invaded her childhood village during his reign and converted the residents into devil worshippers. When King John drove the evil tribe out and saw what the villagers had become, he ordered them all killed. However, “the wisest and the most wicked” of them escaped. It gradually becomes clear that Irena believes herself to be descended from the evil tribe, and that she fears that she will be transformed into a panther if aroused to passion, anger, or jealousy.
Despite her odd belief, Oliver marries her. However, dreading what could happen, she avoids sleeping with her husband. He persuades her to see a psychiatrist, Dr. Louis Judd (Tom Conway), who tries to convince her that her fears are of a more mundane nature. When she discovers that Oliver has confided their marital problems to an attractive co-worker, Alice Moore (Jane Randolph), she feels betrayed.
Irena finally decides to consummate her marriage, but by then, it is too late; Oliver tells her he is getting a divorce. Later, at work, he and Alice are cornered by a ferocious animal. Thinking quickly, he grabs his T-square (which is in the shape of a cross) and tells Irena to go away. After it leaves, they call Dr. Judd to warn him to stay away from Irena, but he hangs up on them when the woman shows up. Attracted to her, he makes the fatal mistake of kissing her. She transforms into a panther and kills him, though he manages to wound her. When Oliver and Alice arrive a few minutes too late, she slips away, back in her human shape, and goes to the zoo. There, she opens the panther’s cage and allows herself to be killed.