Kayo Yamaguchi is a 43-year-old mature woman, a devoted wife and mother who has raised her son well. However, as the years pass, the loneliness deep within her heart grows stronger each day, leading her to spend her nights indulging in masturbation. One night, she was in the kitchen, calmly washing her body with water as she usually did to pleasure herself. At that moment, her son suddenly appeared behind her and discovered her in the act. Caught between shock and confusion, torn by maternal pride and conflicting emotions, she waits to hear what words her son will speak to her.