The Spanish explorer Pizarro captures the Inca god-chief Atahualpa and promises to free him upon the deliverance of a horde of gold. But Pizarro finds himself torn between his desire for conquest and his sense of honor after friendship and respect develops between captive and captor.

Spanish explorer Francisco Pizarro persuades King Carlos V to finance another Peruvian expedition in search of the Incas' gold. Provided only with two priests and Estete, the king's personal representative, Pizarro recruits 167 volunteers and appoints Hernando De Soto second in command. Upon arriving in Peru, Pizarro arranges a meeting with Atahualpa, the divine king of the Incas who has been warned by his followers that the Spanish invasion will lead to disaster. After Pizarro announces to the Inca priests that he, too, is a god, the Peruvian ruler arrives at Spanish headquarters, where Dominican priest Valverde tries to convert him to Christianity. The conversion proves unsuccessful, however, and the Spanish priests demand that Atahualpa be taken prisoner, whereupon the Inca ruler is seized and his escort murdered. Pizarro asks for a ransom in gold large enough to fill Atahualpa's cell, and as the Incas work to fulfill the demand, Pizarro becomes acquainted with the noble leader and is partially convinced of his divinity. As the ransom is delivered, officers in Pizarro's command, fearing Inca reprisals, threaten to mutiny unless Atahualpa is executed, and the priests, unsuccessful in their attempts to convert the Incas, concur. Although Atahualpa guarantees Pizarro's personal safety, the Spanish soldiers sentence Atahualpa, despite Pizarro's protests. The Inca leader dons a golden mask, assuring everyone that the Sun God will not allow him to die. After the execution, Pizarro, with faith in the ruler's prediction, removes the mask to find Atahualpa dead. He then begins to realize the enormity of the crimes he has perpetrated against the Incas.