Terence McKenna and his brother Dennis travel by plane, boat, and foot to La Chorrera, a mission town deep in the Colombian Amazon, in 1971, searching for a psychedelic plant preparation called oo-koo-hé. They never find it, but they do find a large stand of Stropharia cubensis mushrooms, and what follows becomes the basis for Terence's later ideas about language, the I Ching, and his TimeWave theory of accelerating history. Director Peter Bergmann builds the film from photographs and notebook pages from that year, never shown publicly before, layered with animation and voice drawn from Terence's own talks and his book of the same title. Chapters move through the brothers' isolation, a self-described experiment with mushroom dosing, a stone Terence describes as materializing during it, and the UFO theorizing that grew out of the episode afterward. Dennis McKenna and Terence's daughter Klea McKenna contributed documents and approval for the project. The film stays inside the McKennas' own account rather than adjudicating it, presenting hallucination, belief, and theory as one continuous record.