Wife Rin struggles with her husband's frequent business trips and their nearly nonexistent sex life, leaving her with doubts and dissatisfaction. Worried about his possible infidelity, she grows emotionally distressed—until her kind and gentle stepfather begins to comfort her. Feeling lonely and emotionally vulnerable, Rin gradually leans on his warmth and affection. As her deep-seated sexual frustration builds, their bond crosses into forbidden territory, transforming her into someone driven solely by desire.