Iwaoka, Hisae

Window washer Mitsu inadvertantly risks Kageyama's life while trying to save his coworker after Kageyama collapses on the job. In recovery, Kageyama discovers that his immune system has been compromised by exposure to UV rays and he must choose between his job and his health.

Sixteen-year-old Mitsu, a window-washer on the Ring System, a space colony in orbit around Earth, must decide if he should descend to the Earth in an experimental device to try to change the Ring System.

When sixteen-year-old Mitsu, a window-washer on the Ring System, a space colony in orbit around Earth, is asked to man an illegal craft headed for the planet's surface, he must decide between duty and obeying the law and taking the journey of a lifetime.

Mitsu struggles to adapt to his new career as a window washer, but he begins to recognize some of the job's perks, which include befriending coworkers and learning more about his late, absent father.

As Mitsu becomes accustomed to his window-washing job, he meets two new clients, each lonely in their own way, and draws the attention of other employers. And, Sohta takes out his frustration on the Earth's surface after he is demoted from his power-plant job, for which he was overqualified anyway.

While the people of Earth live in a stratified society on a ring surrounding the planet, Mitsu's father has disappeared and Mitsu is forced to undertake his father's profession as a window washer shortly after his junior high school graduation, which allows him a view of the higher levels of society through their windows.