El Santo, the masked Mexican wrestler, investigates a series of kidnappings. He discovers that the mysterious Doctor Caroll is using the victims as part of his experiments to develop an army of monsters. Naturally, El Santo is able to overcome them all - with wrestling!
In 1920s Mexico, the candidates being chosen to succeed the current president, El Caudillo, find themselves at his mercy as he will resort to anything to accomplish his will, including kidnapping, betrayal, and murder.