The face in the abyss

While searching for lost Inca treasure in South America, American mining engineer, Nicholas Graydon 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 by Suarra and the Snake Mother whom he joins in their struggle against Nimir.