The novel concerns American mining engineer Nicholas Graydon. While searching for lost Inca treasure in South America, he encounters Suarra, handmaiden to the Snake Mother of Yu-Atlanchi. She leads Graydon to an abyss where Nimir, the Lord of Evil is imprisoned in a face of gold. While Graydon's companions are transformed by the face into globules of gold on account of their greed, he is saved …