Grace, an ordinary woman from the modern world, awakens to find herself reincarnated as the aristocratic villainess Grace in her favorite romance novel. In the original story, Grace is a promiscuous, greedy woman who toys with the cold‑hearted Duke Zane, then callously dumps him. This rejection is the catalyst that leads Zane to meet the true heroine, preventing a devastating war. Grace knows that if she fails to follow this plot, war will erupt and she will die. To avoid her grim fate, she resolves to play the part of the perfect villainess: make Zane fall for her, then cruelly discard him.

The setting is a fantasy world of dukes, balls, and political intrigue, dominated by the rules of the original novel. Grace’s plan, however, hits an immediate snag. Despite her best efforts to act haughty and manipulative, her genuine, earnest personality keeps breaking through. She cannot bring herself to be convincingly wicked. Instead of being repulsed, the allegedly cold‑hearted Duke Zane becomes intrigued by her awkward attempts at villainy. He finds her endearing and grows deeply attached. Far from letting her go, he declares he will never break up with her and showers her with unexpected affection.

The story follows Grace’s escalating struggle to stick to the “break‑up script” while Zane’s devotion intensifies. She enlists the help of her loyal but eccentric knight Evan, who aids her with deadpan humor and practical support, and her clever maid, who helps her stage villainous scenes. Grace attempts to provoke jealousy by pretending to court another nobleman, but Zane only becomes more possessive. As the tale progresses, Grace’s internal conflict deepens: she must choose between preserving the original story’s outcome and embracing her growing feelings for the man who refuses to abandon her.

Notable narrative arcs include Grace’s failed attempts to manipulate Zane into meeting the story’s heroine, Charlotte; her realization that Zane’s devotion is genuine; and the mounting tension as the possibility of war looms. The manga balances comedy derived from Grace’s earnest blunders and Zane’s oblivious intensity with a sincere romance that gradually undermines the intended “villainess” plot.