A likable old inventor and former stage hypnotist, Karloff has finally developed a device whereby one person can totally control the mental facilities of another. All he needs to find is a person willing to act as a guinea pig, and Ogilvy fits the bill. Karloff's intentions are good, but his wife, Lacey, has developed a cynically selfish attitude after years of poverty spent helping in her husband's experiments. When she sees the newly attained power at her disposal, which includes feeling the sensations of Ogilvy as he undertakes their commands, Lacey's desires become more sadistic and self-gratifying. This is a total reversal of Karloff's intentions, but he can do nothing about it because Lacey proves more powerful than he in controlling Ogilvy. In a last-ditch effort to destroy the monster he has created, Karloff has Ogilvy crash the car he is driving. In this way he also kills himself and his wife, as they also experience the impact and flames of the crash. A subtly menacing film given the proper atmosphere by the mere appearance of Karloff. Director Michael Reeves would direct one more film, THE CONQUEROR WORM (1968), before dying of a drug overdose at the age of 24.