When a gang of modern-day terrorists attack their parents, twelve-year-old Crys Delchant and his older sister, Taylok, are forced back into Rockworld, a unique cavern where crystals are instruments of death and prehistoric beasts proliferate. It has been more than ten years since either has been inside the cavern, and things have deteriorated enormously. A Nehwisna man with a prime crystal has taken over and terrorized the inhabitants, who number in the tens of thousands. The man declared himself Egahi'wa, the god of light, and has killed hundreds of those who resist his rule. Crys has been given a prime crystal as well, but he has only a short time to learn how to use it before he must face Egahi'wa, as the Stone of Life predicted. And the Stone of Life is seldom wrong. But the children are not alone here. Driggett, a stalwart cavern friend, finds them and plots to overthrow Egahi'wa. New friends Aracite, Topaz, and Cameo lead Crys to the Stone of Life. Even Taylok, whose skill with a sling is peerless, aids Crys until he is kidnapped by the Vedetta, a strange group of women. The Hutana, a gigantic wormlike creature and the Fisher Bats, descendants of Pteradactyals, all threaten to end Crys's short life-if Egahi'wa doesn't get him first. Crys Delchant and the Stone of Life is the third novel of a trilogy, following The Cavern and Escape from the Cavern.