A cancer researcher on a remote Caribbean island discovers that by treating the natives with snake venom he can turn them into bug-eyed zombies. Uninterested in this information, the unfortunate man is forced by his evil employer to create an army of the creatures in order to conquer the world.
Fleeing to Dodge City after killing a man in self defence Masterson finds his brother Ed (Harry Lauter) running for sheriff of the town. When Ed is killed by hired guns of the corrupt incumbent Bat is determined to settle the score with violence but he is convinced by the townspeople that the best way to avenge his brother’s death is by taking Ed’s place on the ballot. Bat agrees and wins the election but his new role on the right side of the law will lead him to unexpected confrontations as he finds himself torn between his loyalties to his friends and his duties as sheriff.