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.
Stanley Ridges
Prof. George Kingsley / Red Cannon
Boris Karloff
Dr. Ernest Sovac
Bela Lugosi
Eric Marnay
Anne Nagel
Sunny Rogers
Anne Gwynne
Jean Sovac
Virginia Brissac
Mrs. Margaret Kingsley
Edmund MacDonald
Frank Miller
Paul Fix
William Kane
