Global climate undergoes drastic changes, and the original surface urban facilities suffer severe damage. A few survivors find underground shelters, relying on complete facilities and precious civilization classics to nurture the new generation. Elders impart everything they have, passing survival experience, knowledge, and culture to the younger generation. When the youth grow up and step onto the surface, they survey the environment, build homes, and excavate the technological achievements left by their predecessors. People build a new home in the highlands where nature and technology blend, develop ecological agriculture, construct civilization collection venues, achieve resource recycling and self-sufficiency, and let civilization continue to grow and extend.