Nana, who married her former tutor from her school days, thought she had built a happy family. However, her relationship with her stepson, Shinya, remained strained, leaving her daily life filled with discomfort and tension. Shinya had once worked as Nana's private tutor and had developed romantic feelings for her during that time. Frustrated by Nana's attempts to maintain a proper stepmother-stepson distance, Shinya grows increasingly resentful and begins forcing himself on her to satisfy his desires. Nana believes her actions are a necessary sacrifice to save Shinya. Offering her entire body and soul, she fulfills his twisted desires in a desperate search for her own salvation.