In order to obtain criminal evidence of the gang leader Zeng Chen (Eric Tsang), the policeman Sir (played by Chen Baixiang) ordered his men Xu Ren (played by Shawn Yue), Fei Qiu (played by Lam Chi Chung) and Sha Qiang (played by Chapman To) to enter Zeng Chen's gang as undercover agents. In fact, Zeng Chen also sent his men Hua Dee (played by Huang Haoran) to infiltrate the police force. When they entered the gang, they found that Zeng Chen did not know how to deal with the affairs of the underworld, and his nature was not bad. At this time, Xu Ren and his men were caught by several uninformed female police officers. Xu Ren and others even developed feelings for these policewomen. Soon the top leader of the underworld died, and there were constant disputes within the gang. Xu Ren and his funny men also got involved, and a series of messy and confusing things happened.