The story takes place on a planet where the inhabitants live inside the hollow interior of their world. The society is divided into castes based on their physical characteristics and abilities. The ruling class, known as the Masters, possess advanced technology and control the planet's resources. A young man from a lower caste discovers that he has a unique genetic trait that makes him immune to the effects of the planet's toxic atmosphere. He becomes embroiled in a rebellion against the Masters, who seek to maintain their power and control over the population. The protagonist must navigate the complexities of his society and confront the harsh realities of his world in order to survive and bring about change. Along the way, he uncovers secrets about the planet's history and the true nature of the Masters' rule.
By Poul Anderson · First published 1967 · Genre: Science Fiction, Adventure, Fantasy · 8 chapters