Shiori has returned to her husband's parents' house. This year, it was her mother-in-law's first Bon festival at her parents' house. Her father-in-law, whom she hadn't seen in a long time, looked a little tired and a little lonely. However, he acted tough as a man in front of his son and daughter-in-law. Shiori's father-in-law's masculinity, which is different from her husband's, and his occasional loneliness, touches her heart. One day, she makes her father-in-law's favorite botamochi to cheer him up. The taste is exactly like the botamochi made by the late Tomiko, and Shiori's appearance is exactly like that of his late wife, so her father-in-law bursts into tears and hugs her. Her emotions are uncontrollable and her father-in-law has sex with Shiori. However, the sexual act is different from that with her husband. Shiori feels love for her father-in-law's ex-wife, so she decides to only have sex for one week during the Bon holiday, and although she feels guilty about her husband, she rushes into sex with her father-in-law.