In tough economic times, Yukie Mizukami's husband suffers a pay cut, forcing her to start working as a private tutor from home to support the household. Her student, Satoru, begins showing affection and making advances toward her, and Yukie, unable to resist, promises to sleep with him if he passes his exams. Inspired by his serious dedication, Yukie starts finding joy and purpose in life again. Meanwhile, her husband Tetsuya grows suspicious of her behavior and begins feeling intense jealousy. When Satoru successfully gets accepted into university, their relationship escalates, culminating in full intercourse. Discovering them in the act, Tetsuya is consumed by rage and despair, sending the story into a dramatic downward spiral.