Based on a novel by Alfred Aloysius Horn and Ethelreda Lewis, two whites find a missionary's daughter abducted by an African tribe and bring her back.
In Africa Trader Horn (Harry Carey) and Peru (Duncan Renaldo) go up river in a boat to trade with natives; but Masai warriors say no. Horn and Peru shoot a crocodile, and Peru finds a lion cub. At night missionary Edith Trent (Olive Carey) arrives, and Horn warns her that drums warn of juju. She is going to Opangu Falls to get her daughter Nina, who has become a fetish, and Horn promises to follow her. At the falls Horn and Peru find Edith dead. Peru goes on with Horn. On the plain they see zebras, wildebeests, giraffes, ostriches, baboons, leopards, hyenas, warthogs, gazelles, wild dogs, impala, buffalo, and a jackal. Horn shoots a rhinoceros that killed a man. They are surrounded by natives. Horn gives the king a music box, but their rifles are taken. Horn notes several tribes, and they see a man tortured. The white woman Nina (Edwina Booth) comes to Horn and Peru. Horn has their African gun-bearer Rencharo (Mutia Omoolu) say they came from her mother. Nina makes the natives leave; but when she whips Peru, he does not move. She has Horn and Peru tied on crosses upside down but stops the burning, and they are untied.
Nina takes Horn, Peru, and Rencharo in a canoe across the lake. Nina refuses to go on until she is going to be left behind. Horn tells Peru no fire so they won't send a signal. Horn watches with Rencharo's spear. The four are tired and hungry. They see a lion kill an animal and fight with other lions. They shout to scare away the lions. A lion goes after Nina, and Rencharo kills it with his spear. They get meat before the vultures. They wait for elephants to leave a water-hole. Peru embraces Nina, but Horn stops them. They run from natives. Horn acts as a decoy and is followed by Rencharo. Horn and Rencharo swing on a vine over crocodiles to an island. At night Horn and Rencharo sneak away on a raft, but Rencharo is killed. Peru protects Nina from a leopard, and they kiss but are surrounded by Pygmies. Nina speaks to them, and they are allowed to go with them. Horn tells another trader that he is going back, but he sees Peru and Nina coming in a canoe. Horn has Peru and Nina leave on the boat without him. In the final scene Horn sees Rencharo's spirit in the sky, and he accepts a new gun-bearer.
This realistic adventure story shot on location in Africa is a landmark in film-making. The savvy Trader Horn shares his knowledge and wisdom with young Peru as audiences get a chance to see native Africans playing themselves. The skill and courage of the Africans is represented by their gun-bearer Rencharo.