In 1560, a Spanish mission sets off up the Amazon looking for El Dorado. Among the soldiers is the conquistador Lope de Aguirre, accompanied by his daughter Elvira. It is not long before their problems start: their boats rot in the humid climate, illness spreads among the crew, the native Indians are exceptionally hostile or refuse to cooperate. Worst of all, however, is the internal strife which divides the group. Ursua, the leader of the expedition is killed and Aguirre replaces him with Guzman, chosen to become "King of Peru". Death by natural causes supersede executions and Aguirre, a bloody dreamer, marked by fever, decrees the illusory "Free State of Peru" as the company continues its vain odyssey.