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 the 16th century, the Inquisition condemns Count Orloff, a vampire and sorcerer to death. In the 19th century, the vampire Madame Kostoff arrives in Mexico and buys the house where the vampire was buried and revives him.