Plot summary
Following the events of The Maze of the Beast , Lief, Barda and Jasmine continue their journey to the Valley of the Lost to retrieve the seventh and final gem of the Belt of Deltora, the diamond. The three travel along the river Tor, passing villages that have been raided by pirates as they attempt to cross, narrowly avoiding a bridge guarded by the Shadow Lord's shapeshifting Ols. When they stop to rest, they see the pirate ship that had captured them and Dain in The Maze of the Beast and find a boat to row to it as the pirates argue over whether to give Dain to the Grey Guards, lest they risk the wrath of Doom, leader of the Resistance. A fire and a fight break out on the ship, started by the pirates' captured polypan, who escapes with Dain into Lief, Barda and Jasmine's boat. The polypan successfully rows against the flooding currents of the river away from the pirate ship and toward shore, but flees ashore as soon as it is able, stranding the party in the boat as the current washes them away.
The following morning, they awake outside the magic city of Tora, where Dain's parents and the exiled royal family are believed to have sought refuge, only to find the city deserted, as the Torans had refused to help Endon after years of refusal from the royal family and broke their vow to aid him, banishing them from the city. The revelations seemingly crush Dain's spirit, and they take him from the city at his request, encountering Doom and the acrobat Neridah outside Tora. After Dain confronts Doom over lying to him about knowing Tora was empty, Doom and Neridah are sent into Tora to pass through its evil-purifying magic to prove they are not Ols. Lief takes the opportunity to question Doom over his past. Dain returns to the Resistance with Doom, who warns the trio against journeying to the Valley of the Lost and of the Guardian who keeps the diamond, but Neridah parts with him, desiring to return home with Lief, Barda and Jasmine.
Despite her claims, Neridah refuses to leave the group when chances arise to return home, so they sneak away during the night to enter the Valley of the Lost. As soon as they enter, they encounter hundreds of ghostly people and the Guardian, who binds them to his will, including Neridah, who had followed them into the Valley in search of the diamond. The Guardian reveals his four pets, Greed, Envy, Pride, and Hate, and treats the group to a feast before revealing they can play a game to find his true name to acquire the diamond, though they will be trapped in the Valley if they lose. Neridah refuses to play and is allowed to leave, while Lief, Barda and Jasmine accept the Guardian's challenge, as the diamond's powers will curse them if they steal it.
A riddle in a mirror provides the clues to the Guardian's name, including the fault of one of the Guardian's pets, which the trio work out from the clues the Guardian had discreetly given them in conversation, a glass ornament in the palace that Barda solves by recalling his palace guard days, and the sum of differences between two pictures of hermits in a rug. They successfully deduce the Guardian's name to be Endon, the king of Deltora, and learn that Doom had previously visited the Valley and won the game, but did not take the diamond because of his shock at the Guardian's true identity. Although the Guardian gives them a diamond, Lief realizes it is not the real diamond and confronts the Guardian, who reveals that Neridah stole the real diamond and refuses to disclose her whereabouts. He realizes that they are the ones the Shadow Lord has warned him about and tries to take the Belt of Deltora from Lief, but is repelled by its magic and attacked by his pets, revealed to be vile growths created from his own body. After Lief severs the pets from the Guardian to save him, he reveals that Neridah is in the stream, having tripped, fallen and drowned due to the diamond's curse. Lief completes the Belt and the Valley of the Lost disappears and all of the ghostly people in are freed, who reveal themselves to be the people of Tora and the Guardian's prior victims, while the Guardian is revealed to be Fardeep, the previous owner of Rithmere's Champion Inn who the Shadow Lord had instructed to pose as Endon in hopes of breaking the spirits of potential resistors. With all seven gems restored to the Belt, the group next set their sights on finding the heir to the throne of Deltora.
