Three years ago, when Ayako's daughter entered the workforce and left home, her husband also left home after he was with another woman, leading to a divorce. Ayako had noticed his affair, and had received most of his house and assets as compensation, so she had no regrets. Six months ago, her daughter got married, and now she lives happily with her daughter and her husband. However, every night, the couple have sex, and Ayako's body gets hot when she peeks at them. One day, Ayako sniffs her son-in-law's underwear while he is in the bath and masturbates. Later, her son-in-law finds out about it, and she is swept away and embraces him...