Kitty Carroll, an attractive store model, volunteers to become a test subject for a machine that will make her invisible so that she can use her invisibility to exact revenge on her ex-boss.
Two bumbling service station attendants are left as the sole beneficiaries in a gangster's will. Their trip to claim their fortune is sidetracked when they are stranded in a haunted house along with several other strangers.
University professor George Kingsley is struck by gangsters while crossing the street, leaving him with brain damage and one of the gangsters, Cannon, paralyzed. Kingsley's friend Dr. Sovac attends to both men, and when Cannon offers him a reward for aiding his recovery, Kovac transplants part of Cannon's brain into the dying Kingsley's skull, creating a dual personality.
