An insurance investigator tumbles onto a series of similar deaths, by brain hemorrhage, of patients of a psychiatric clinic in France where therapy involves a device which can implant visual imagery in the minds of patients, ostensibly to help them relax.
Practical Effects
The dream machine: gloriously unconvincing medical terror.
Acting
Rod Cameron's granite jaw vs. European character actor chaos.

Director
Montgomery Tully
Trivia, insights & behind the scenes
British studios routinely shot two versions simultaneously—one for UK release, one 'continental' cut with added sleaze for European markets. This likely explains the 'sweet-fleshed beauty' tagline grafted onto sci-fi paranoia.
Released the same year Britain's Mental Health Act reformed asylum conditions, the film's evil clinic weaponizes post-war anxiety about institutional power—therapy as conspiracy before Kubrick made it prestige.