Zhang Xuan is young and promising, and has repeatedly solved strange cases in Beijing, winning the reputation of a superb detective. His good friend, Master Li Kui, is known as the master catcher. The two have a very good relationship, but they often compete in solving crimes. One day, Master Li Kui had just solved a case and used the case as a question to test Zhang Xuan. Can Zhang Xuan successfully solve the mystery? But this ordinary competition became the starting point for many causes and connections that followed.