Yuka Hirose lives with her husband and his father. Her father-in-law is kind and considerate, while her husband is dedicated to his work. Yuka longs for a child and desires intimacy with her husband. One day, her husband drops a shocking confession: "I don't want kids" and "I won't have sex." Heartbroken and disappointed, she feels her hopes crumbling. Seeing her distress, her father-in-law begins to worry about her, gradually growing attracted to her despite himself. Initially hesitant, he eventually succumbs to desire, overwhelmed by her voluptuous, alluring body. They begin a secret affair, meeting daily and nightly to satisfy their burning passions. Before long, Yuka's body begins to show signs... A deeply emotional, intense relationship unfolds between her and her father-in-law—tender and gentle at times, strict at others, but always fiercely passionate.