Introduction: Strange cases have been unleashed in Chang'an City. At the scene of the crime, there are six large characters written in blood, "After the instrument is discarded, a new emperor will be established." Rumors arose for a while, and the people in the court were panicked, to stabilize the court for the common people. Wu Zetian assigned Dali Temple Qing Di Renjie to investigate the murder case within five days. The eunuch Song Yi appointed Liu Yiyi from Shenyu Mansion to assist. The two parties secretly competed in order to catch the real murderer first, but they were frequently blocked during the investigation. They were almost injured by the general Baitong who cheated the corpse at midnight. Through the sky, the mysterious masked man and the Southern Xinjiang dancers are scheming. Di Renjie and his team's investigation has become more and more bumpy. The five-day deadline is approaching. Can Di Renjie find out the real culprit behind it?