After the death of her husband's parents, Maki Hojo and her husband inherit the family home as stated in the will, leading them to live together with her younger brother-in-law. As the days pass, the brother-in-law is touched by Maki's kindness, and his feelings for her gradually grow stronger until he can no longer suppress his urges. Meanwhile, Maki has been going through a sexless marriage and is left with pent-up desires. Though she knows it's wrong, her body gives in to instinct. As a result, she becomes deeply entangled in a forbidden relationship with her brother-in-law.