John Robie is a reformed jewel thief who was once known as "The Cat." robie is suspected of a new rash of gem thefts in the luxury hotels of the French Riviera, and he must set out to clear himself. Meeting pampered heiress Frances, he sees a chance to bait the mysterious thief with her mother's fabulous jewels. His plan backfires, however, but Frances, who believes him guilty, proves her love by helping him escape.