Rena, a wife who takes care of her father-in-law, who is getting old and has a short time ahead of him. - For Rena, who was originally a grandfather's child, caring for her father was not a hardship, and the communication she had with her father-in-law was invaluable. - Her husband, who doesn't like the two of them, plans to separate them. - However, Rena's feelings for her father-in-law grow stronger, and eventually she actively takes care of her father-in-law, Shimo, behind her husband's back. - Gradually, the two become a man and a woman, and their bodies overlap day and night, covered in kisses and caresses that are more intense than a married couple...