The film intricately weaves together two narratives set thirty years apart, both centered around Karamakate, an Amazonian shaman and the last remaining member of his tribe. His journey unfolds alongside two different scientists: first, he partners with Theo von Martius, a German ethnographer, in 1909, and later with an American botanist named Evan in 1940. Their common quest is to discover the elusive, sacred yakruna, a fictional plant revered for its mystical properties.
In 1909, Theo, who has been entrenched in Amazonian culture while battling a severe illness, navigates the waters in a canoe with Manduca, a localized individual he rescued from the clutches of forced labor on a rubber plantation. The situation is grave, and Karamakate, while hesitant to engage with a westerner, uses a mystical powder referred to as “the sun's semen” to prolong Theo's life. Despite Theo's desperate need for yakruna to cure his ailment, Karamakate refuses to accept any form of compensation and sets forth with them on their search.
Fast forward thirty years, we find a much older Karamakate, now visibly disconnected from his tribes' customs, encountering Evan. The botanist reveals he aims to continue Theo's quest, but Karamakate, feeling his knowledge is diminished, initially hesitates to assist. Evan, wielding a book that belonged to Theo—detailing his final expedition—shows Karamakate an image of himself, referencing it as his chullachaqui, or hollow spirit. Intrigued by Evan’s commitment to plants, Karamakate reluctantly agrees to help. However, unbeknownst to him, Evan has ulterior motives; his true goal is to secure a consistent supply of disease-free rubber trees, a critical resource as American supplies dwindle due to wartime disruptions in Southeast Asia.
Throughout both journeys, the narrative portrays a Spanish Catholic Mission situated alongside an Amazon tributary. In 1909, it is managed by a cruel priest, displayed as a tormentor of orphan boys involved in any “pagan” activities. By 1940, a deluded Brazilian claiming to be the Messiah runs the mission, accepting visitors only when he believes they embody the Biblical Magi. Karamakate eventually earns his respect by healing the priest's wife. Meanwhile, the children who suffered under the priest's care have evolved into disturbed, violent disciples.
As Theo seeks refuge from the mission, he arrives at a frontier post, faced with the impending invasion of Colombian soldiers amid the booming Amazon rubber industry, witnessing the sacred yakruna desecrated by intoxicated men—something that ignites Karamakate’s fury as he destroys the abused plant. In Evan’s journey through 1940, Karamakate unveils the plant's origins nestled in the breathtaking, barren dome-shaped mountains known as Cerros de Mavecure. He presents Evan with the last remaining yakruna flower, preparing it with great care; its hallucinogenic properties usher Evan into a profound transcendental experience, portrayed through a shift from black-and-white to color as a representation of its impactful nature. The film concludes with a transformed Evan, captivated by a vibrant dance of butterflies, suggesting a profound connection to the journey he has undertaken.
