Yumi worked herself to the bone as a single mother, determined to give her daughter Ami a happy life. Her sacrifices pay off when Ami finds a good husband and gets married. Yumi is delighted to see her daughter happy, yet her own desires as a woman still smolder deep inside. Once she begins seeing Ami's husband, Hiroshi, as a man, she cannot suppress her arousal and turns to masturbation to keep herself under control. She never imagines that Hiroshi himself has witnessed her intimate act...