One day, Shigeru accidentally witnesses his parents having sex and becomes intensely aroused by his mother Kaede's passionate appearance. From that night on, Shigeru can't stop himself from touching Kaede's body in search of pleasure. Though she resists, Kaede begins to experience a new kind of pleasure unlike anything with her husband, gradually drawn into these sensations. Shigeru's advances grow bolder each day, eventually causing profound changes within her body.