Rena is a wife who is caring for her father-in-law, who doesn't have much time left. Rena was originally close to her grandfather, so caring for him wasn't a burden, but a way to communicate with him. Her husband, who doesn't like the happy relationship between the two, plots to separate them. However, Rena's feelings for her father-in-law grow stronger, and before long, she actively cares for his private parts, hiding them from her husband. Gradually, the two become a man and a woman, and they kiss and caress each other more passionately than a married couple, making love day and night...