The story begins with a brief history of the protagonist, John T. Unger. John grew up in a small town called Hades but was later sent to an Eastern boarding school. It is here that John meets Percy Washington. After the two become friends, Percy invites John to spend the summer with him at his home in Montana. On the journey home, Percy reveals to John that his father is the richest man alive. When the two boys arrive at the Washington's mansion, which is hidden in the mountains of Montana, John is indulged in luxury. He finds out that the Washingtons live on a diamond mine, and that is how Braddock Washington, Percy's father, has made his wealth. The Washingtons explain that their only fear is being found out because no one has ever seen the mine or the land that they live on. As John's summer continues, he meets Kismine, the beautiful sister of Percy, and he falls in love with her. Kismine reveals to John that at the end of the summer, he will be murdered in his sleep so that the secret of the mine is not revealed. She explains that it is not a big deal and all members of the family have had to sarcfice some of their closest friends. Together, Kismine and John plan an escape for that very night, but before they can leave, the home is invaded. Airplanes fly over and gun down the resort. John rescues the girls, and they run off into the mountains. Here, he witnesses Mr. Washington offering God a diamond bribe in return for saving his home. Mr. Washington's offer is rejected, and the story ends with John and the girls realizing that they are without money so life will now be very different. The pilots are also killed when Mr. Washington forfeits his home and implodes the mountain, revealing the world's largest diamond.