Beijing, in the future: To make the most efficient use of the limited space, the city has been divided into three sectors that can rotate, sink into the ground, and fold up using a sophisticated construction. Following a strict plan, only one sector is unfolded at a time, allowing people to go about their activities. Contact across sector boundaries is prohibited. Lao Dao, a worker at a waste disposal facility in the Third Sector, embarks on an adventurous errand into the shielded First Zone and uncovers a dark secret behind the foldable walls of this beautiful new world.