Edward Jessup is a university professor of abnormal psychology who, while studying schizophrenia, begins to think that "our other states of consciousness are as real as our waking states." Jessup begins experimenting with sensory-deprivation experiments using a flotation tank, and he travels to Mexico to participate in an amanita muscaria ceremony where he experiences bizarre, intense, paradigm-shifting imagery. The professor then returns to the U.S. with a mushroom tincture and begins taking it orally before each session in the flotation tank where he undergoes a series of increasingly drastic psychological and physical transformations.