While performing during a wrestling bout, Santo spills some of his blood near the audience. Soon this blood is scooped up by a mysterious attendee, Dr. Freda Frankenstein (Gina Romand), who spirits it back to her laboratory where she keeps two of her monstrous creations, the half-ape Truxon and patchwork man Ursus. Frankenstein needs Santo's essence to create more of her powerful youth serum, which provides temporary relief from the ravages of aging. Unfortunately her experiments now indicate she needs a bigger supply, so the lady doctor sets up an elaborate trap to lure in the healthy wrestler. Accompanied by the lovely Elsa (Sonia Fuentes), Santo journeys to the remote lab, where all hell soon breaks loose. (In Spanish language, with English subtitles).