Duke Chu wants to hold a small celebration with close officials and the emperor for his birthday. He requested the Purple Clothing Bureau to do a sword dance for him. On the day of the celebration, one of the Purple Clothing Bureau members, attempt to assassinate Duke Chu. Chen Rou Yu prevents the assassination and asks to be part of the investigation. Through the investigation of Chen Rou Yu, she realizes that Qi Yan isn't the emperor that she thought he would be. (Source: cassiopeiastars at MyDramaList)