Convicted criminal Charles "Butcher" Benton goes to his death in the state prison, cursing the three men who double-crossed him following an armored-car hold-up: "Squeamy" Ellis, Joe Marcelli and Paul Lowe, his attorney and leader of the gang. He vows to return and kill them and dies without revealing the location of the stolen money. Detective Chasen is determined to keep working on the case until the stolen loot is recovered. Benton's body is taken to Professor Bradshaw and his assistant for experimentation, and they manage to restore him to life, making him practically indestructible in the process. He takes off after the three men, getting rid of everybody who stands in his way. He is impervious to police bullets. He kills Ellis and Marcelli, while Lowe seeks police protection. Benton takes to the sewers to recover the hidden loot and the police are powerless to stop him.
"300,000 Tropes of Terror!":
- The Butcher: The indestructible villain of the title is "Butcher" Benson.
- Cane Fu: When attacked Joe Marcelli batters Benson with one of his crutches. It does him no good.
- Get into Jail Free: When the police deny him police protection, Paul Lowe punches the sergeant so he will be arrested and placed in a cell.
- Gone Horribly Right: Dr. Bradshaw's experiment was intended to restart a corpse's heart by chemical stimulation and a massive jolt of electricity. It succeeds, but while Bradshaw believed the heart would be restarted for a few minutes, the process restores Benson fully to life and renders him Nigh-Invulnerable. Benson then murders Bradshaw and his assistant.
- The Speechless: Benson speaks in the first scene of the film, but the electrical process that returns him to life burns out his vocal cords, rendering him mute for the rest of the movie.