Natsume lives with her husband and her brother-in-law. She harbors secret feelings for her brother-in-law, emotions she can no longer suppress. One day, after drinking heavily, he passionately kisses her and they begin having sex without a condom, culminating in an unprotected creampie. From that moment on, she becomes addicted to intense, fulfilling creampie sex with him—something she never experienced with her husband. Her life takes a twisted turn as she begins a double creampie-filled existence. Her relationship with her brother-in-law deepens, awakening her to new pleasures and igniting an insatiable desire within her.