The young second wife, Koi, tries to please her husband Kouichi in their nightly activities. However, Kouichi can't get it up as he wishes. Disgusted with her husband, Koi starts having a physical relationship with her stepson Hajime. One day, Kouichi catches the two in the act and, to his surprise, finds himself getting hard at the sight. Excited by the scene of his wife and son, Kouichi lies about going out but instead watches them and masturbates…
