Husband and wife intimacy has ceased, and Chitose, the frustrated stepmother, can no longer suppress her desires. Hidden lust simmering beneath the warmth of family life is gradually noticed by her son-in-law, escalating into an illicit affair within the household. Her voluptuous, soft body—especially her obscenely large, bountiful breasts—increasingly tempts her daughter's husband. Though aware of her true feelings, he becomes hopelessly obsessed with her allure, unable to resist committing adultery right under the family's nose. Emotions spiraling beyond familial boundaries give rise to an intense, forbidden drama.