In 1998 a group of archaeologists is nearly drowned while diving into the depths of a sacrificial pool high in the Andes of Peru. They are saved by the timely arrival of the renowned scuba diving hero Dirk Pitt, who is in the area on a marine expedition. Pitt soon finds out that his life has been placed in jeopardy as well by smugglers intent on uncovering the lost ancient Incan treasure. Soon, he, his faithful companions, and Dr. Shannon Kelsey, a beautiful young archaeologist, are plunged into a vicious, no-holds-barred struggle to survive. From then on it becomes a battle of wits in a race against time and danger to find the golden chain, as Pitt finds himself caught up in a struggle with a sinister international family syndicate that deal in stolen works of art, the smuggling of ancient artifacts, and art forgery worth many millions of dollars. The clash between the art thieves, the FBI and the Customs Service, a tribe of local Indians, and Pitt, along with his friends from NUMA, two of whom are captured and threatened with execution, rushes toward a wild climax in a subterranean world of darkness and death – for the real key to the mystery, as it turns out, is a previously unknown, unexplored underground river that runs through the ancient treasure chamber. The fallen are told to come back and haunt those who took their treasure.