Sumaki and her daughter-in-law Chisato lived together. Among them, Chisato and the son-in-law were having an affair. One day, Sumaki's sister Yuri returned. She said she had a fight with her husband. Everyone listened to Yuri complain. One day, Chisato's sister Reiko returned from Hawaii. Yuri saw Chisato and her son-in-law having an affair. Recently out of touch, both Yuri and Reiko seduced the son-in-law and had a relationship with him. And when Natsuki went out for a company drinking party, Chisato, Reiko, and Yuri the three of them cornered their son-in-law, and a four-way sex began...
