Above the wasteland, the upper ground is a neon paradise, and the underground is a dark cage. Lin Xiaoman—the most extraordinary technical genius in the underground district, whose parents were originally from the upper levels above ground, both mysteriously disappeared. He fought his way up to the surface relying on surveying and weapon mastery, breaking evaluation records, crushing wealthy second-generation heirs, tearing apart the disguise of veterans, and keeping the defiant in line. Yet beneath the prosperity, every pioneering mission is batch-"replacing" pioneers—doubles wearing other people's faces to die in people's places. The aloof technician Shen He beside him is precisely the survivor who adopted a name to save her mother. A feast filling the eyes conceals the population replacement dark secrets of the "Mending the Heavens Project". And his patron stands at the other end of the truth.