Field ethnobotanist Dr. Petra Calles leads a four-person expedition into the Peruvian Amazon to investigate documented traces of an uncontacted settlement in the Madre de Dios basin. After losing satellite communication and encountering an unmapped river, her team discovers an elaborate botanical navigation system grown into living trees over decades. Following the markers, they meet Kaya, a woman guarding a three-hectare managed botanical garden containing potentially revolutionary medicinal compounds. There Petra finds her father, Eduardo, alive after seven years, who chose to stay and build a comprehensive evidentiary record rather than risk losing the knowledge to commercial extraction interests who had intercepted his earlier notebooks. Using an unmapped tributary exit known only to Kaya's community, the team escapes surveillance, reaches a river outpost.
