Aspiring performer Sally Bird poses as French cabaret star "Mademoiselle Zaza" in order to work in American "King" Kelly's London nightclub. Later she is kidnapped by the gangsters who seek revenge upon Kelly, as he had escaped from New York without paying them their protection money. After escaping the gangster, Sally admits her true identity to Kelly, who, having fallen in love with her, keeps her as the star of his show.