Set in Tokyo's seedy underbelly, the story follows Izumi, a demure and dutiful housewife married to a famous romance novelist. Despite her seemingly perfect life, Izumi feels imprisoned and unfulfilled. She begins to yearn for something more than the mundane routine of her daily life. One day, she decides to take a part-time job at a grocery store, where she meets an enigmatic woman who leads her to a world of eroticism and danger. As she delves deeper into this new world, Izumi's encounters become increasingly intense, awakening desires she never knew she had.

Eventually, Izumi's life spirals into a chaos of dual identities, mingling her once quiet existence with a dark exploration of her newfound freedoms. She becomes entangled with Mitsuko, a literature professor leading a secret double life, whose influence pulls Izumi further from her former self. As her secret world grows, so do the perils, pushing Izumi to confront the extreme boundaries of her own desires and the consequences they bring. The narrative builds up to a point where her dual lives are on the verge of collapsing, creating a tension that threatens everything she once held dear.