The Diamond as Big as the Ritz recap

John T. Unger accepts schoolmate Percy Washington's invitation to a hidden Montana estate and discovers a palace built above a mountain-sized diamond. The Washingtons preserve their fortune by keeping the location secret, imprisoning accidental discoverers and killing guests once their visits end. John falls in love with Percy's sister Kismine, who warns him that he too is scheduled to die. Before the family can act, aircraft locate and attack the estate. Braddock Washington's attempt to buy divine protection with a giant diamond fails, and the mountain and palace are destroyed. John escapes with Kismine and her sister Jasmine. The jewels Kismine saves prove to be worthless rhinestones, so the three leave with no fortune, intending to seek refuge with John's family in Hades.

John T. Unger leaves his affluent family in Hades, Mississippi, to attend St. Midas's, an elite school near Boston. There he befriends Percy Washington, a quiet boy who claims that his father is the richest man alive and owns a diamond larger than the Ritz-Carlton hotel. Percy invites John home for the summer. Their journey takes them by train to a tiny Montana settlement and then by private transport into country absent from maps. As the ordinary landscape gives way to evidence of immense hidden wealth, John realizes that Percy's boast may have been literal rather than childish exaggeration.

John arrives at the Washington estate, a dazzling palace in an isolated valley, and meets Percy's parents and sisters, Jasmine and Kismine. The buildings, furnishings, baths, and entertainments display wealth on a scale that makes ordinary millionaires seem poor. Percy explains that the estate sits upon a single diamond mountain. John is intoxicated by the luxury and by Kismine's beauty. Yet the household's isolation is as striking as its magnificence: its comforts depend upon servants with no freedom to leave and upon a secrecy that separates the Washingtons from the rest of the country.

John learns the origin of the fortune. Braddock's grandfather Fitz-Norman Washington discovered the diamond mountain and understood that exposing it would destroy the scarcity on which diamonds derive their price. The family therefore concealed the territory, manipulated official surveys, and built a private domain around the deposit. Their continued wealth depends less on selling the whole mountain than on releasing small quantities while preventing knowledge of its existence from escaping. The story of the estate makes clear that its splendor has always required coercion and that visitors who learn its location can never simply return to ordinary society.

John and Kismine fall in love, but their romance brings the danger of the estate into the open. Kismine matter-of-factly explains that guests are killed after their visits so the family's secret will remain secure; John is expected to meet the same fate. He also learns that aviators who have accidentally approached the property are held captive rather than allowed to report what they saw. Kismine's affection makes her willing to warn John, though she has been raised to regard the underlying cruelty as ordinary. John begins looking for a way to survive and escape with her.

The secrecy protecting the Washingtons fails when aircraft appear over the valley and attack the estate. John, Kismine, and Jasmine seek a route out while Braddock refuses to accept the collapse of a world in which money has answered every problem. He offers an immense diamond to God in exchange for the preservation of his property, but no bargain saves him. The attack destroys the palace and diamond mountain, and Braddock and his wife are lost with the estate. John escapes with Kismine and Jasmine. Kismine has brought stones she believes will support them, but they are rhinestones; because diamonds were common at home, she thought the imitations must be the valuable rarity. Nearly penniless, the three head toward John's home in Hades and an ordinary life outside the vanished enclosure of wealth.

Aircraft attack the Washington estate after its location is finally discovered. Braddock Washington attempts to bargain with God by offering an enormous diamond, but no rescue follows. The mountain, palace, and most of the family fortune are destroyed, and Braddock and his wife do not escape. John flees with Kismine and Jasmine. Believing that Kismine has saved valuable jewels, he imagines that they can rebuild their lives, only to learn that the stones she brought are rhinestones; she assumed the imitation gems were rarer because real diamonds were commonplace at home. The survivors are left with almost nothing. John nevertheless chooses a future with Kismine, and the three young people set out toward Hades, Mississippi, confronting ordinary poverty for the first time.