Nie Yuan went to the Public Security Bureau to experience life before joining the League, while Huang Jue was more natural, and his natural attributes fit this role very well. In order to better shape the role, Xin Peng lived in Chongqing to experience life one month before shooting.

Behind the scenes:

This film is Li Xiaofeng's second full-length work, because it has been recognized by the main actors, and the film payment only accounts for a quarter of the shooting cost.

In order to fully integrate into the role, Luo Jin stayed in the cast for 60 days. He also lost 20 pounds and grew a beard.

Luo Jin auditioned three times, the most important one being the scene in the audience.