Rina (18), a surly girl who's a part-time club member with no interest in romance or exams, has no idea what she wants to do and spends her days wasting her youth and her big breasts. One day, she suddenly feels aroused and rushes to the hospital. She 's diagnosed with an incurable disease that increases her "sexual desire 100 times". Her daily life becomes overwhelmed with worldly desires. The cure for relief, the doctor tells her, is simply to satisfy her sexual desire through sex with a man. However, boys view Rina as "scary". One day after school, Rina can't help but be tempted by a male classmate who happens to be paired with her while cleaning and she ends up forcibly inviting him to join her...