Scientist Dr. Laurience (Boris Karloff) has colleagues who respect his work and value his research. But when they suddenly snub the extensive work he's recently done, this causes him to go a little crazy. Upset by such rejection, he uses them to test one of his newest inventions, a machine programmed to switch the minds of people around him without their knowledge. Among the victims are his rivals and the fetching Dr. Clare Wyatt (Anna Lee).