ObscureHollywood.net’s review published on Letterboxd :
Prof. Marcus Monserrat (Boris Karloff) has invented a machine for mental enhancement. He talks Mike Roscoe (Ian Ogilvy) into trying out his apparatus. As Marcus and his wife Estelle (Catherine Lacey) bombard Mike with the emanations from the machine, the mental processes of the trio meld. Marcus and Estelle seize control of Mike’s mind.
Marcus expects that the process of mind control can be utilized for human good, but Estelle intends to use their control of Mike for her own enjoyment. Marcus agrees to the theft of a fur. Estelle is thrilled by the danger and excitement associated with the theft. She forces Marcus to let her experience the exhilaration of a high speed motorcycle ride. Greater elation ensues when she has Mike beat up his friend Pete, the owner of the motorcycle. In spite of Marcus’ protests, Estelle proceeds to the greatest thrill of all, the savage murders of two young women.
Marcus has fought unsuccessfully to take control of Mike. However, during a final car chase with the police, Marcus seizes control from Estelle and guides Mike into the destruction of all three of them.
The increasingly maniacal elation of the aged woman as she controls and shares the senseless blood lust of Mike is simultaneously repulsive and gripping.
Karloff and Lacey add distinction and a good deal of acting ability to the cast. A well done and intriguing film, cheaply made with minimal sets.
The meteoric career of director/writer Michael Reeves ended after only three films. At age 25, he died of a drug overdose.