Prince Yongyan sneaked into Tianlao late at night to visit his mentor Zhu Gui, who was imprisoned for serious crimes. Seeing that Zhu Gui was covered with bruises and was obviously tortured to extract a confession, he couldn't help but feel heartbroken. He was convinced in his heart that his mentor had been framed. He immediately turned around and entered the palace to beg his father, Emperor Qianlong, for a lighter sentence. However, Qianlong flatly refused on the grounds of "severe punishment to serve as a warning to others". In desperation, Yongyan volunteered to investigate the case personally, but he did not realize that this move happened to fall into the trap of others.
Yongyan immediately set off with his confidants Li Wei, Wang Bi, and the dark rich Cha Jia Nansheng specially arranged by his mother. Unexpectedly, as soon as he left the capital, he was attacked by unknown people. Unfortunately, Li Wei was stabbed and injured. The few people could not go on their way, so they had to go to the "Huamanlou" to rest and recuperate. Unexpectedly, the female owner of the inn, Jin Xinger, had evil intentions and secretly drugged them. After several people fell into coma, the Prince's Token that Yong Yan carried with him was accidentally lost.
At night, Li Wei's injury suddenly worsened. Several people rushed to seek medical treatment, but on the way to seek medical treatment, they bumped into the killer who had attacked them before. Only then did they suddenly realize that there was a mysterious organization "Youheng Division" that was pressing on secretly, with the purpose of preventing them from finding the truth...
