The novel uses the "underground boxing ring" as a secret background and tells the undercover story of the male protagonist Chen Jin (codenamed "Ye Xiao"), who disguises himself as an underground boxer and sneaks into the "dark night fighting ring" in order to find his brother Lin Xiao who has been missing for three years. As the investigation deepens, he gradually uncovers the collusion of interests between the underground boxing ring and the police, corruption and evil forces (such as criminals led by "Mario"), as well as the truth about the "drug scandal" and "disappearance case" in which his brother was involved. In the process, he formed a temporary investigation team with the beautiful social reporter Meng Jing (to fulfill the last wish of his predecessor Zhang Yan to investigate the underground boxing ring) and the criminal policeman Cai Wenxuan (who issued a military order to crack down on the underground boxing ring) to jointly fight against the evil forces, and finally succeeded in destroying the underground boxing ring network and bringing the criminals to justice.
