Wife Natsuki couldn't give up on having a child with her husband, who became paralyzed due to an accident. After repeated discussions, the couple settled on a last resort: "surrogate sex with her father-in-law, Kiyoshi." Believing it would be easier to feel affection for him than a complete stranger, they proceeded. However, Kiyoshi became increasingly aroused by Natsuki's presence, growing more passionate over time. Under the pretense of conceiving a child, he relentlessly pursued Natsuki's body, disregarding his role as a father-in-law and repeatedly creampieing his son's wife without hesitation. With her husband's permission as justification, Natsuki gradually found herself emotionally drawn into the incestuous relationship with her father-in-law.