A certain otome RPG takes place in the Valschein Kingdom, where dark hair is stigmatized to an abnormal degree. Yumiella Dolkness is the daughter of a count, hated from birth due to her pitch-black locks—and she is also the hidden boss! In a twist of fate, at five years of age, Yumiella recalls memories of her past life in Japan. Uninterested in the romance aspect of the original game, she begins to dedicate herself to training her rare dark-type magic.

Despite this, Yumiella's goals are clear: avoid becoming the hidden boss and stay out of the limelight. Upon entering the magic academy, however, she shakes the foundation of the kingdom when her level 99 status comes to light. Whether a physical brawl or magic duel, her abilities are unmatched, and coupled with her black hair, she sticks out like a sore thumb. To make matters worse, the original heroine begins suspecting she is the demon lord! Can the deadpan noble girl achieve her wish of a peaceful life?