Dr. Frieda Frankenstein, daughter of the Dr Frankenstein of Mary Shelley fame, has been continuing and expanding on her father's work in Mexico. She uses a youth serum to not only keep herself going, but to hire/control her Mooks — they behave themselves, or they won't stay young and healthy. Unfortunately, the serum has to be re-administered regularly. Frieda's been on the juice for so long that's she's developed a resistance to it. Unless she can create a new formula, she will die from old age soon.
Fortunately, she discovered by accident that El Santo's blood contains a huge amount of the "TR factor", the substance that helps humans heal. All she needs to do is capture Santo; she can then use his blood to produce a new youth serum that will work on her. She sends her red-shirted thugs out to collect Santo's girlfriend Norma and leave a message behind. Santo and Norma's sister Elsa head out to rescue Norma ... but they don't know just how many people are dependent on Frieda's youth serum.
This movie includes:
- Bloodless Carnage: Played straight in the first Mandatory In-Ring Sequence; the match announcer talks about how Santo is bleeding heavily from his opponent's illegal blows and we don't see one drop. Averted with Truxon and Ursus later in the film.
- Brainwashed and Crazy: Frieda hypnotizes Norma and orders her to gouge Santo's eyes out.
- Chekhov's Self Destruct Switch
- Eye Scream: The guards have this reaction to Norma's orders (noted above).
- Fountain of Youth: The youth serum.
- Frankenstein's Monster: Two of them, actually.
- Ursus is a "traditional" monster, though without the green skin tone
- Truxon is half-man, half-beast, produced through an experimental serum. Frieda considers him a failure, since he is regressing to pure animal.
- Grave Robbing: The movie opens with Tuerto and some mooks digging up a body for Frieda.
- HeelFace Turn: All it takes is a little sympathy and very basic first aid to switch Ursus over to Team Santo.
- Immunity Disability: This sets off the whole plot — Frieda Frankenstein has developed an immunity to the youth serum she needs to survive.
- James Bondage: Santo gets chained up twice.
- Mad Scientist
- Mad Scientist Laboratory: A bit sparse on the decor, but it's got all the essentials.
- Meaningful Name: Tuerto, the leader of Frieda's mooks, is missing one eye. (His name is Spanish for "One-Eyed", and the English sub calls him that throughout.)
- Obvious Stunt Double: The scene where Frieda tears Santo's mask off is shot from behind Santo ... more accurately, from behind someone who's at least six inches taller than Santo. Masks in lucha libre really are Serious Business—but was it that hard to find someone who looks convincingly like Santo from behind?
- The Power of Love: Invoked by Santo after Norma's hypnosis.
- Red Shirt: Frieda's minions all wear this uniform. Well, except for the undercover minions ....
- Shirtless Scene: Justified for the Mandatory In-Ring Sequences. Not so justified when Santo is captured, and the thugs removed his shirt before chaining him up to await Frieda Frankenstein's pleasure ... Oh, yeah.
- Sound-Only Death: Truxon's fate.
- Versus Title
- You Have Failed Me: When one of the thugs screws up big time, Frieda refuses to give him his next dose of youth serum. He ages and dies in front of the rest of the crew in minutes.