The Vanyanna State invaded across the border. The 19-year-old King of Qi Pei Yanzhi was ordered to take charge. He fought hard to turn the tide of the war, but was ambushed in the final battle of Honggu and his entire army was wiped out. The King of Qi, who had escaped death and returned to the court, was held accountable by the King of Yun and his military power was removed. Faced with the King of Yun supporting the young emperor to ascend the throne and secretly seizing the imperial power, the King of Qi and the young emperor reached a tacit understanding and chose to temporarily give in. Since then, the King of Qi no longer asked about the affairs of the court, and privately changed his name to Pei Zhao and began to play around. In fact, he was secretly investigating and vowed to find out the truth about the defeat that year. While investigating the case of the missing silver for disaster trafficking, Pei Zhao met Su Ci, the young official of the Mingjing Bureau, in Qingshui County. He was interested in her cold personality and superb ability to solve cases, and they traveled together. On the way, Pei Zhao and Su Ci met Xie Beiming, the young owner of Feiyun Villa, and Dong Rushuang, the daughter of the Poison King, and the four formed a detective team. As the cases were solved one by one, the danger gradually approached. Su Ci's true identity is revealed, the truth of the war gradually surfaces, the detective team is involved in the power struggle in the court, and many tests such as truth, love, friendship, and family affection follow one after another.