When songstress Trilby O'Farrell (Marian Marsh) meets fascinating hypnotist Svengali (John Barrymore), she leaves everyone behind to pursue a career on the concert circuit. But what she doesn't realize is that she can perform only at the mind controller's command. Eventually, the young woman suffers under such intense control. Luis Alberni plays Svengali's sidekick, Gecko; Archie Mayo directs this atmospheric drama.