A man named Tony is captured riding the horse of Lee Corey, a missing delivery man for a local mining company. Tony claims to have bought the horse from two men, but the sheriff believes he has murdered Corey and stolen the horse. Tony is sent to the gallows, but escapes hanging with the help of Corey's mistress and sets out to find the real killer.
Landru, a French businessman, arrives Mexico with the idea of promoting their fighters, what nobody knows is that besides Landru promoter and fighter is a mad scientist who seeks to alter human genetics mixing it with the animal to make stronger and fiercer to their gladiators.
