A closed single-parent family: a corrupt incest

After his divorce, Chieri lives in a small wooden apartment with his son Taichi. Despite being poor, Chieri lived a happy life, but she accepted a proposal from Tabuchi, the manager of the supermarket where she works. However, Taichi couldn't allow his mother to be taken by others. Just as soon as Taichi comes home from his part-time job, he goes to see Tabuchi's sex with his mother at home... "Mom won't give it to anyone!" And Taichi devours his mother's body right next to Tabuchi...