Mother Yumi, widowed and having raised her daughter to adulthood, lived a quiet, ordinary life. Her daughter married and moved in with her, creating a peaceful household. One night, by chance, Yumi peeked into her daughter and son-in-law's bedroom—and was shocked. The gentle, serious son-in-law she knew was passionately making her daughter climax intensely. Witnessing this scene awakened her repressed memories of being a sex-addicted creampie slut, and her long-suppressed desires surged uncontrollably.