OBA-201 A married woman named Chisato Kashiwagi invites her lover to her home and indulges in sex while her husband is away.

Today is Saturday, and from morning, Yuuta, the son, has been in high spirits. This is because he's going to the pool with his father who took a summer vacation. And Chisato, who was supposed to stay home alone, was also excited. This is because she planned to invite her 'fuck buddy' over while her husband and Yuuta were out… As soon as she saw her husband and Yuuta leave, she immediately brought Kenji, her fuck buddy, into the house. "Let's have lots of sex today!" And so their 'time unlimited, no limit on number of times FUCK' begins...