Famous African explorer Trader Horn (Harry Carey) sails to a small village with Peru (Duncan Renaldo), his best friend's son. That night, their camp is disrupted by the arrival of Trader's friend Edith Trent (Olive Carey), a missionary searching for her missing daughter, Nina (Edwina Booth). Shortly afterwards, Trader and Peru come across Edith's dead body. Continuing the expedition, they discover Nina is now the evil leader of a nearby tribe, and plans to sacrifice them.