Aika, a mother who lost her husband in a traffic accident three years ago, has been raising her son Yu alone while taking care of her father-in-law, who has no other relatives. While being busy with daily life, Yu, who always saw his mother's hardworking figure, secretly harbored the desire to become independent soon and repay her kindness. One day, Yu saw his supposedly ill father-in-law, who was lying in bed, touching Aika's body with obscene gestures while she devotedly took care of him.