The story takes place in a modern metropolis called Haicheng. On the surface, it is no different from any other bustling city. But deep beneath its streets lies a vast ecosystem known as the “Quiet Zone,” a self-contained, self-sustaining biosphere with unique plants and animals whose air is lethally poisonous to people on the surface. Thirty years ago, the Quiet Zone’s founders, a group of scientists and engineers, signed a pact of silence and secretly protected it from exploitation or destruction by outsiders. Now the first generation of guardians is growing old, while a multinational biotech company has detected the Quiet Zone through illicit means and begun secretly surveying it with plans to seize it. The core rules of protection and sacrifice are these: the guardians cannot use direct violence to expose the Quiet Zone’s existence. They must act within the rules, turning the city itself into a maze and a weapon, and use their ingenuity, deception, and even self-sacrifice to drive away the threat.
