After the "Skyfall Disaster" three hundred years ago, the floating city monopolized civilization and the people on the surface became "ground rats." The "civilization resonance" awakened in the forests of Rusty City can awaken old machines and reveal the natural disaster to be the conspiracy of the floating city in order to find the core of civilization. He works side by side with Ling Shuang, the Dawn organization, using machines as blades, vowing to let the echoes of civilization shake the world.
