In 1560, several score of Spaniards conquistadors, and a hundred Indigenous peoples of the Americas slaves, march down from the newly conquered Inca Empire in the Andes mountains into the jungles to the east, in search of the fabled country of El Dorado. Under the command of Gonzalo Pizarro (Alejandro Repullés), the men, clad in half personal armor, pull cannons down narrow mountainous paths and through dense, muddy jungle. On New Year's Eve, reaching the end of his supplies and unable to go on without more information, Pizarro orders a group of forty men to scout ahead by raft down river. If they do not return to the main party within one week with news of what lies beyond, they will be considered lost. Pizarro chooses Don Pedro de Ursúa (Ruy Guerra) as the commander of the expedition, Don Lope de Aguirre (Klaus Kinski) as his second-in-command, fat nobleman Don Fernando de Guzmán (Peter Berling) representing Spanish Royal Family and Brother Gaspar de Carvajal (Del Negro (actor)) to bring the word of God. Also accompanying the expedition, against Pizarro's better judgment, are Ursúa's mistress, Doña Inés (Helena Rojo) and Aguirre's teenage daughter, Florés (Cecilia Rivera, in her only film role).