My Royal Nemesis is a fantasy romantic comedy that follows Kang Dan-shim, the most feared and notorious villainess of the Joseon era. After being sentenced to death, she mysteriously awakens in modern-day South Korea inside the body of struggling actress Shin Seo-ri. Determined to rewrite her fate, Dan-shim navigates an unfamiliar world filled with technology, celebrity culture, and corporate power. Her path soon collides with Cha Se-gye, a ruthless chaebol heir known for his cold personality. As sparks fly between the unlikely pair, their love-hate relationship leads to unexpected romance, laughter, and a second chance at destiny.