During the school summer break, the nine-year-old Elisabeth joins her family in the rainforest where they live together with the Pemón tribe close to the Devil’s mountain. When after an accident Mom needs to fly Dad to a hospital, Ilse volunteers to look after her three-year- old brother Leo. However, instead of paying attention to her brother, Ilse’s nose is stuffed in a book. When finally Ilse looks up, she discovers that Leo has disappeared. All signs show that he has wandered towards the jungle. Elisabeth has to bring him back home before their parents return. Thus begins an adventurous journey through the jungle, during which she must outwit a trio of dangerous poachers who are capturing rare species in the rainforest. Ilse discovers Leo at the foot of Devil’s Mountain, where members of a mysterious mystical tribe and animal friends of a previously undiscovered species help the children in their battle with the poachers.