Sonia, having been reincarnated as the “ラスボス (last boss)” witch from an anime, is aware that her fate is to be judged and slain as the evil witch. To escape that tragic destiny, she accepts a marriage annulment with the prince—a key trigger of her downfall in the original timeline. As compensation for the annulment, she gains Ville, the knight she adored in her past life, as her servant. She hopes to live quietly in her homeland, but Ville distrusts her, believing she is still the wicked witch. Their tense, bittersweet, and sometimes comedic relationship begins as she seeks to change fate.