Seitaro Hino has lived a life secluded from society, together with his mother since childhood. He easily gets ill whenever he inhales the polluted air outdoors, so he spends his days by indulging in self-studies and literature in his apartment, darkened by the boarded-up windows. One day, when his mother suddenly dies, Seitaro is forced out into society and surprisingly his respiratory disease seems to have been cured by itself. Nevertheless, all these sudden happenings and new impressions are too much for him, and he is soon struck by aphonia. His aunt, Yoko Oshikawa, decides to take care of him until he has adapted himself to the new environment and is able to stand on his own.