Far in the future, humankind has evacuated the Earth in order to preserve it. Humans now reside in a gigantic structure that forms a ring around the Earth, thirty-five kilometers up in the sky. The society of the Ring is highly stratified: the higher the floor, the greater the status. Mitsu, the lowly son of a window washer, has just graduated junior high. When his father disappears and is assumed dead, Mitsu must take on his father's occupation.
