A mad doctor (Bela Lugosi) and his helpers (John Carradine, George Zucco) lure girls to his lab for brain work, to help his wife.

The discovery of a perfectly preserved caveman prompts a mad scientist to attempt a daring brain transplant.

A police lieutenant is determined to bust the gang of crooks selling defective automobile tires.

An independent truck driver organizes his fellow truckers to resist the efforts of a crooked trucking company exec to bring all drivers under his control. When the trucker’s brother dies…