During the war between Sheng and Yu kingdoms, Sheng was defeated. On her deathbed, the Sheng princess tasked her maid, Ayue, to impersonate her, marry for peace, and steal Yu's defense map. Meanwhile, in Yu, Prince Chu Ruheng, branded a "rebellious son," seeks the truth behind his mother's mysterious death. A "fake princess" and a "disgraced prince" cross paths in a treacherous palace. Amid suspicion and love, they join forces to uncover secrets and fight for peace.