After losing her husband, mother Sakura raised her daughter alone. The daughter grew up and got married, continuing to live with her mother. Their quiet, ordinary life carried on until one night, when Sakura accidentally spied on her daughter and son-in-law's private moments. She witnessed her mild-mannered, serious son-in-law passionately making her daughter climax repeatedly. The scene burned into her mind, awakening her long-buried memories of being a sex-addicted creampie slut, and an uncontrollable desire began to stir within her.