OBA-235 A married woman named Kyouko Hattori invites her lover to her home and indulges in sex while her husband is away.

After husband and son Shinichi started getting into sumo wrestling a few months ago, this Saturday they were planning to go watch it together. Then came Saturday, leaving Keiko at home, the husband and Shinichi went out to watch sumo wrestling… A few minutes later, a young man arrived at the house. The man's name is Tanaka; he had met Keiko and started a relationship with her at the supermarket where they both worked part-time. Until the husband and son returned, a day of non-stop action began right then and there…