At the medical faculty of Harvard, doctor Eddie Jessup wants to discover altered states of consciousness. To do that, he performs a controversial and dangerous experiment. Doctor uses a sensory deprivation chamber – a pod filled with water, which separates him from all the external stimuli. Over time, scientist intensifies his experience, taking a hallucinative brew from Mexico.

In effect, Eddie undergoes a terrifying voyage to the very beginning of the human consciousness. He loses himself more and more in the visions, which, with time, go beyond the mind, the consciousness, and even interfere with his body.
The experiment gets totally out of control.

Ken Russell was one of the most individualistic and controversial directors of British cinematography.