The continuation of the story of the soldiers from Guangdong and Hong Kong: troops divided into two routes

At the request of the Hong Kong government, the mainland public security dispatched three officers - Dong Xujianjiang as Jing Sheng, Guo Lin as Guo Lin - to infiltrate a mainland criminal gang in Hong Kong. However, their brutal methods and an accidental killing of a dancer by Guo Lin caused the police to refuse to take responsibility for them, leaving the three as abandoned spirits. Dong insisted on fulfilling his duties as a public security officer but was unmasked as an undercover agent by fellow criminals from his hometown.

To combat the criminal activities of new immigrants in Hong Kong, the police decided to recruit a detective among the smuggled migrants who would serve as an undercover agent for two years in exchange for permanent residency rights. Superintendent Cheng arranged for Li Xiangdong, Qi Jingsheng, and Guo Xuejun to collaborate with informants. Soon after, Jingsheng met his comrade Ah Hu through whom he was introduced to Ah Lang and Ah Bao, who had been wanted by the police for many years.

During a transaction, the identities of Li Xiangdong and others were revealed by the Jiang brothers. Forced to kill to cover their tracks, Ah Lang and others later slaughtered Da Da to avenge the Jiang brothers, unknowingly creating enmity between the two groups. Dong decided to infiltrate the Lang Bao Group, so these people came together to plan a bank robbery.

Before the action, Ah Lang discovered that the operation plan had been leaked and uncovered Dong's true identity. The two groups immediately engaged in a fierce battle inside a building.