A young Canadian nurse (Betsy) comes to the West Indies to care for Jessica, the wife of a plantation manager (Paul Holland). Jessica seems to be suffering from a kind of mental paralysis as a result of fever. When she falls in love with Paul, Betsy determines to cure Jessica even if she needs to use a voodoo ceremony, to give Paul what she thinks he wants.

When the naval construction designer Oliver Reed (Kent Smith) meets the Serbian Irena Dubrovna Reed (Simone Simon) in the zoo, he flirts with her and they sooner fall in love and marry each other. However, Irena is afraid of an ancient course of her town that women can not be touched by a man, otherwise she will transform in a panther, and the couple does not consummate their marriage. Irena is sent for treatment with the psychiatrist Dr. Louis Judd (Tom Conway), while Oliver looks for "consolation" with his colleague Alice Moore (Jane Randolph). When Irena sees that she is losing Oliver to Alice, she becomes jealous and hateful, leading to a tragic end.

Jeff Bailey seems to be a mundane gas station owner in remote Bridgeport, California. He is dating local girl Ann Miller and lives a quiet life. But Jeff has a secret past, and when a mysterious stranger arrives in town, Jeff is forced to return to the dark world he had tried to escape.