A devoted fan of the light novel series Astrea Empire Records, Amamiya Nagisa is deeply in love with Noin, the story’s villainous duke. She dies and is reborn as Frau Flame Rose, Noin’s younger sister, in the very world of her favorite books. Though Frau and Noin are not related by blood, the empire strictly forbids romantic relationships between siblings. Refusing to let anyone else claim her beloved brother, Frau embraces the role of a villainess and resolves to destroy every possible romance flag that could lead Noin away from her. She adopts a fierce, possessive attitude, using her knowledge of the original plot to intercept any woman who might get close to him. The story follows Frau’s relentless scheming at court, her clash with the original heroine Elisa, and the tension between her desperate love and the taboo that stands in their way. As she manipulates events and battles rival nobles, she must also grapple with the question of whether her actions will eventually draw Noin’s attention or bring about a tragic end.