Brilliant filmmaker Roberto Gavaldón collaborated with screenwriter José Revueltas to create this distinctly Mexican variant on the time-honored Evil Twin plot: this time, it’s the great Dolores del Río as both a meek, bespectacled manicurist and her mercenary, man-eating sister. But in this case, envy proves to be a greater sin than avarice. The film was based on an unproduced screenplay commissioned for Bette Davis, who eventually made her version in 1964—Dead Ringer, directed by Paul Henreid.