Salvia divinorum is a plant in the mint family found only in small, shaded plots in Oaxaca, Mexico, where Mazatec shamans have long used it as an entheogen during healing rituals they call spirit journeys. Its Latin name translates to "sage of the seers," and its active compound, salvinorin A, is the focus here as researchers examine how the plant produces its effects and why it differs chemically from most other psychoactive substances. The film lays out competing theories about the plant's origins: whether it grows wild, was cultivated by the Mazatecs, or came from another indigenous group entirely, and it revisits ethnobotanist R. Gordon Wasson's claim that salvia is the plant the Aztecs recorded as pipiltzintzintli, a claim later scholars have disputed based on Aztec descriptions of separate male and female varieties. Rather than settling the question, the film treats salvia divinorum as a case study in how little is actually documented about a plant with centuries of ritual use behind it.