A man’s brain is put into an ape after being executed. Now he’s out for revenge on the men that set him up. This is simple and bizarre at the same time. Onslow Stevens is really over the top as a D.A. Rod Cameron plays a friendly reporter. At least George Zucco is the scientist who wants to save mankind. The mystery is how Ellen Drew and Paul Lukas ended up in this. Maybe someone at Paramount was mad at them.
Scott Webster is on trial for murder. He says he’s innocent. A hotel bellhop named Tips (Cliff “Ukelele Ike” Edwards) says he saw him shoot a man. Scott testifies he came to town looking for a man named Larry Reed (Robert Paige). He approaches gangster W.S.Bruhl (Paul Lukas) who tells him to meet them at a hotel room later that night.
Scott goes and knocks on the door. Bruhl sends the man to answer it. When he opens the door a gunman standing behind Scott opens fire and tosses the gun at Scott. He picks it up. Scott’s sister Susan (Ellen Drew) takes the stand and it’s flashback time.
They come from a small town where Scott is the church organist and works in the post office and is quite content. Susan wants the big city and some excitement. Things aren’t going well in the city. She runs into Larry Reed at the unemployment office and they eventually get married. She writes to Scott telling him all about it.
After the ceremony a party is tossed at their hotel suite. The next morning she wakes up. Larry’s gone. In her room is Munn (Gerald Mohr) one of Bruhl’s gang. He tells her Larry doesn’t exist. Since she’s broke he tells her he can get her a job as a hostess at a cabaret. She’ll have to be friendly, real friendly, to the customers. She’s asked to describe her life but clams up. Scott is found guilty and sentenced to the chair. End of flashback.
On the night of his execution he’s visited by Dr.Parry (George Zucco). He wants Scott’s brain after he’s done with it. Scott gets a laugh out of that and says okay. After he meets his fate Parry transfers his brain into an ape. Thirty-two days go by and Scott starts remembering his promise of vengeance on everyone who had him set up. He breaks out.
His first victim is the D.A. He’s tossed out a tenth story window and then brought back up to his apartment. Every bone on his body is broken. The ape goes to Susan’s. She doesn’t see him but his old pal Skipper the dog does and he can’t stop wagging his tail and follows him everywhere.
Bruhl wants Susan brought to him. His henchman Sleeper is real nervous and thinks they’re all doomed. Munn is sent to get her. The ape watches from a tree branch when Munn drives up. He won’t be driving back. The papers now refer to the Mangler Murderer.
The ape’s not done by a long shot. In an alley a beat cop spots Skipper and sits down on a crate. Parry comes by and says he’s going to get the cop a big promotion with what he has to tell him as the ape looks on.
This has to be seen to be believed.