An African trader and a white jungle goddess join forces against a hostile tribe.

Deep in the heart of Africa, famous hunter, explorer Aloysius Horn, known as Trader Horn due to his bartering skills, tells Peru, the son of his best friend, that he was the first white man to set eyes on the river on which they are sailing. When their boat approaches a small African village that is bustling with activity, the natives welcome the visitors, and Trader asks to be taken to the chief. Though Trader warns Peru of the savage nature of the natives, Peru is nevertheless shocked when he sees a human skeleton displayed on a public cross. The white men's visit is soon interrupted by the ominous sound of a distant drum beat, known as "ju-ju," which the Africans, as well as Trader, know signals the impending attack of the brutal Masai warriors. Trader explains to Peru that when the Masai and the Kukua tribes get together, "the devil is certainly involved," and suggests that they move on. That night, the men, with their African guide, Renchero, set up camp, but they are awakened by the unexpected arrival of the white missionary woman, Edith Trent. Edith, a friend of Trader, whom Trader calls the bravest woman in all of Africa, informs him that she intends to go above the Opanga Falls and into Isorgi country in order to find her missing daughter Nina, who is believed to be living among the Isorgi. Trader warns Edith of the dangers of traveling during ju-ju and offers to accompany her, but she refuses, claiming that the presence of a male with guns will only startle the warriors into violence. Edith consents, however, to allow Trader and his companions to follow her at a distance, on the condition that he continue her search if something should happen to her. Not long after the expedition begins, Trader and Peru discover Edith's body by the river. They proceed to bury it under rocks and mark it for witch doctors, who will later dig it up and make charms out of it. As they promised Edith, Trader and Peru take up her search for Nina, and on the trail find themselves in the company of giraffes, leopards, ostriches, warthogs, zebras and other creatures. After Trader and Peru finally locate Nina, they soon realize that she is the sadistic white goddess of the village in which she lives, and that she plans to sacrifice her new visitors by tying them to crosses and burning them. At the last minute, though, Nina has a change of heart, orders their release, and plans an escape with them from the bushmen, who have turned on her. The goddess escorts the men across the lake, and they brave the perils in their path, including a lion attack. During the course of their journey, Peru and Nina fall in love, and when they kiss, Trader insists that he separate from them for the remainder of the trip. The sound of the enemy tribe's approach sends them scattering, Peru with Nina, and Trader with Renchero. The next morning, Trader discovers that Renchero has sacrificed his life in order to protect him and mourns the loss of his friend. Meanwhile, Peru and Nina are shown to safety by a tribe of pygmies, and they are eventually reunited with Trader. Peru tells Trader that he is taking Nina back to civilization to educate her, and as they sail off, Trader sees an image of Renchero in the clouds on the horizon.