Santo turns his attention in to the supernatural in his third film. As the film opens we are introduced to three creepy silent thieves who are staging a midnight raid on a jewellery shop.
During the course of the theft, the night watchman shoots one of the robbers in the forehead, with no apparent effect. The bandits fend off arriving detectives and make their escape — delivering their loot to a man in a medical tunic and a hood. It seems they are zombies — revived criminals controlled by an evil mastermind.
The robbery is assigned to three detectives to investigate (Armando Silvestre, Irma Serrano and Jaime Fernandez) along with the disappearance of a noted professor who had recently returned from a research trip to Haiti.
When the man’s daughter (Lorena Velazquez, who appeared in a number of lucha films — including a two-film stint as half of the femme wrestling duo, Las Luchadoras) appeals to the authorities for assistance, Silvestre wisely calls on Santo for help.
Santo almost instantly runs afoul of the zombie master. He thwarts the kidnapping of the female of the trio and, later, prevents the zombies from abducting children chosen as experimental subjects, from an orphanage. One particularly bizarre element to the film being that both the madman and Santo can tune each other in on closed circuit television. Santo literally watches as the fiend lays his plans.
In an attempt to put an end to this unwanted meddling (is there ever wanted meddling?), the hooded mastermind abducts Santo’s next ring opponent (co-scripter Fernando Oses) and turns him into a killer zombie. The plan unravels when Santo managed to short circuit his control belt.
The daughter and the detectives of course end up in the mastermind’s hands, and it’s El Santo to the rescue!