American adventurer Harry Steele (Charlton Heston) earns a living as a tourist guide in Cusco, Peru but plans to make his fortune by finding the Sunburst, an Inca Empire treasure. He possesses an ancient carved stone which gives the location of the Sunburst but has no means to travel there. He is also menaced by his dubious associate Ed Morgan (Thomas Mitchell (actor)) who wants the treasure for himself and tries to have Harry killed.