Kaede and her son, Shintaro, have been having a physical relationship for several years, even though they knew it was wrong. - However, recently, since Shigefumi quit his job and started working from home, they have been unable to have sex and their desire has increased. - One day, Shigefumi goes jogging. - Shintaro seizes the opportunity and begs Kaede for sex. - Despite being frightened by the thrill, from that day on, the two of them started dating in the limited time that their father was away.