After Yu Shirong returned from studying in the South China Sea, he went to Chang'an City and became a red-clothed detective of the Monster Extermination Department, specializing in investigating supernatural cases related to monsters. Among them, Yushi Rong Yushirong met his true destiny, Li Qingyan, and the two worked together to quell the monsters in Chang'an City and even the entire southern country, leaving behind a beautiful legend.