Shen Weiwan, the concubine of Dajing, was forced to marry her eldest sister to Beishuo. She was also coaxed by her sweetheart Gu Yanci into taking the "position of a true concubine" and lurked in the East Palace to do secret work.
When she first met Xiao Jin, the prince of Beishuo, she was repeatedly tempted, but she discovered a clue when delivering information - the information had been tampered with, and Xiao Jin was attacked as a result. The truth is revealed: Gu Yanci colluded with the rebel forces and wanted to use her to stir up war between the two countries; but Xiao Jin, who seemed indifferent, had rescued her ten years ago, and the birthmark on her wrist was a token, and the temptation was just to protect her.
During the crisis, Xiao Jin stained her clothes with blood, revealed the truth about her replacement marriage and made her the crown princess; Shen Weiwan also lost her ignorance and helped Xiao Jin put down the rebellion and negotiate for peace. After her marriage, she accidentally discovered fragments of the late emperor's edict, and discovered the secret of her life experience that she was the late emperor's granddaughter. Faced with the Queen Mother's difficulties and the throne game, the two worked together to break the situation, transforming from "marrying pawns" into "co-governing partners", writing a legendary love across national borders.
