Colonel Sam Givens, U.S.Army Corps of Engineers is assigned to Saudi Arabia to aid the government in developing a secret island off the coast of Hijaz, a hostile district of Saudi. Hijaz is controlled by powerful Prince, Sulayman ibn Saud, who is against the project because he knows the island abounds in raw diamonds. Hoping to destroy the project, the Prince hires Niki Tamani, a covert security specialist who he directs to infiltrate the project.
Sam visits the island and while swimming in a fresh water pool, discovers strange black stones which he suspects are diamonds. As he steps from the pool, he's bitten by a cobra and immediately flown to England for medical care. While recovering, he is visited by his superior, General Mark Wykopft, who informs him he is to be sent home and retired. Knowing his only hope of wealth depends on returning to the island and harvesting the diamonds, Sam tells the general the secret and makes him a partner - his plan is to contact a friend in Bangkok and have him market the stones anonymously. Sam is given thirty days to harvest the diamonds and sell them.
Sam leaves the hospital and flies to Bangkok to see Jon Petit, a diamond cutter who served under him as an MP in Viet Nam. He offers Jon a job on the island project and casually shows Jon two of the black stones, claiming he bought them from a beggar in Saudi. Jon cuts the stones and discovers they are rare colored diamonds, known to the trade as `Tears of Eve' - worth over a million dollars. Jon doesn't believe Sam's story about the beggar, and accepts the job in Saudi, thinking Sam will lead him to the source of the `Tears of Eve'.
Upon arriving in Jeddah, Sam goes directly to the island, where he harvests a large parcel of the diamonds. As he steps from the pool, he is accosted by five Arab Bedouins of the Hanafi tribe - relatives of Prince Sulayman. He kills all of them and leaves the bodies in a mangrove swamp. Later that night, Sam is murdered in his hotel room by Cinnamon Patel, a female agent of Niki Tamani.
Jon arrives in Jeddah and, with the help of an English speaking Saudi, Aram Cindi, follows Sam's trail to the island. Jon retrieves some diamonds from the pool and emerges to find Aram Cindi has discovered the five dead Bedouins. While he is helping Aram remove the bodies from the swamp, Jon is stung on the toe by a poisonous cone shell. Aram leaves to inform the police, just before a large band of Hanafi Bedouins catch Jon on the island. The Bedouins think Jon killed the five Arabs; he is whipped, severely beaten, and taken to Al Fama, a remote fort in the An Nufad desert. The toxic poison from the cone shell has left him delirious.
Prince Sulayman uses the fort at Al Fama to secretly cut the `Tears of Eve' he gathers from the island and sells anonymously through the auction in Geneva, Switzerland. His actions have not gone without notice. Powerful members of the government have discovered the tremendous wealth he has secretly accumulated and consider him a traitor.
A group of religious policemen attack the fort at Al Fama, creating a scene of chaos. During the fray, Jon is set free and, still in a state of partial delirium, stumbles blindly into the desert where he is rescued by one of the policemen. He is returned to a field hospital in Yanbu where a government official, Dr. Esberi, finds him near death. Dr. Esberi has Jon transferred to a major hospital in Riyadh for special care. Jon heals over a four week period, during which time Dr. Esberi becomes a close friend.
When General Wykopft learns of Sam's death, he sends a covert force of eight special forces troops to the island, via the Red Sea. They slaughter the security force, harvest a large parcel of the diamonds, and escape to the Egyptian coast.
Just before Jon leaves the hospital, Dr. Esberi informs him tha