Several years after losing her husband, Nanami finally felt like the weight on her shoulders had lifted when her daughter got married. Her daughter's marriage seemed happy, and she started to look forward to becoming a grandmother. However, every night, she would unknowingly soil her underwear from the sounds of her daughter's moans and pleasure. Then, Nanami became obsessed with wondering how good her son-in-law was in bed, to the point where she would secretly watch her daughter's conjugal activities and masturbate.
