Mamori Wataya, a girl accustomed to blending into the background at school due to her plain appearance, finds excitement in befriending Soushi Fuji, a classmate with a cunning demeanor and a penchant for revenge. Inspired by Fuji's villainous ways, Wataya contemplates embracing her own dark side. Encouraged by Fuji to undertake mischievous deeds, Wataya experiences the thrill of breaking rules, mirroring the antics of the villains she admires in anime and manga. As she delves into this newfound realm of naughtiness, Wataya grapples with the desire to explore more sinister acts, despite her reservations about crossing ethical boundaries.