Captain Garin Featherstone is a shattered postwar flyer with little hope of fitting back into civilian life—until the enigmatic Antarctic explorer Gregory Farson offers him work, purpose, and a flight south into the unknown. What begins as a routine expedition to investigate a strange purple-blue haze over the ice becomes a plunge into mystery, when Garin's plane is seized by an invisible force and driven beneath the frozen crust into a hidden green world of towering plants, alien power, and impossible life. There, Garin is rescued by the lizard-like Folk of Tav, healed in a magnificent underground civilization of stone halls, glowing lights, and advanced machines, and drawn into a society ruled by ritual, scholarship, and ancient memory. As he learns their language and customs, he discovers that he has been chosen for a dangerous purpose tied to Thrala, the radiant Daughter of the Ancient Ones, and to the looming conflict with the Black Ones, whose corruption and cruelty threaten Tav's future. Guided by Urg, Trar, and the loyal Ana, Garin must venture toward the Caves of Darkness, carrying a strange weapon and a desperate hope of bringing the Daughter back from the depths. This edition has been fully restored with modern typesetting, custom cover design.