A mysterious killer has been strangling women in a variety theater, and the police decide to bring Santo into the investigation. Santo suspects the killer is hiding undercover as one of the theater employees and must discover his true identity before more women are murdered.

• Cinematográfica Norte
• El Santo
• María Duval
• Roberto Cañedo
• Ofelia Montesco
• Carlos López Moctezuma
• Begoña Palacios
• Alberto Vázquez
• Eric del Castillo