Seven years into her marriage, Kyoko, a nurse, lives a peaceful family life with her husband, who works as an internist at the same hospital. However, one day, her husband makes a shocking proposal: "Could you spend just one night with the director's daughter?" He plans to offer Kyoko's body to the director's daughter in exchange for securing the position of chief of internal medicine. Confused and stunned, Kyoko is coldly persuaded by her husband's words: "It's not cheating if it's between women." Reluctantly, she heads to meet the director's daughter, convincing herself, "Just once... If I endure it just once, my husband will get promoted." But as the director's daughter skillfully uses her words and touch, Kyoko's rationality begins to waver, and her body starts moving on its own. An unfamiliar pleasure she's never experienced before tears apart her mind and body, drawing her into overwhelming confusion...