Yun Jiayue, the capital's most notorious unruly young lady and the princess of the Prince of Zhenbei's household, is ordered by imperial decree to marry the frail Crown Prince, Zong Yichuan. Hoping to call off the engagement, she strikes a three-year deal with the Crown Prince and agrees to play the role of Crown Princess temporarily. She knows nothing about music, chess, calligraphy, or painting, but she is highly skilled in martial arts and has a bold, spirited personality. She stirs up trouble at the academy, talks back to imperial consorts, and protects her husband, turning the capital upside down. The seemingly delicate and sickly Crown Prince is actually a master strategist. As the two gradually develop feelings for each other from being mere partners in a deal, they embark on a spirited, sweet, and exhilarating historical romance.