The Hong Kong police received a videotape that showed three police officers were suspected of using violence against a man in the street. For this reason, members of the Hong Kong Police Complaints Division began to investigate members of the PTU. Li Yongsen (Simon Yam), a police officer of the PTU, knew that the police officers in the videotape were himself and his colleagues, and the one who was subjected to violence was a lawbreaker nicknamed "Da Da Cheng". So Ah Sen decided to conceal the incident from his superiors and find "Da Da Cheng" to settle the matter privately. At this time, "Da Da Cheng" was nowhere to be found. Police officer Ma Ba (Li Guolin) of the PTU was rejected for seeking help from the police force due to financial problems, and was knocked down and used violence by his superiors during an operation, and Ma Ba was forced to a dead end in life. The three teams of police became tense overnight. Can they solve their respective problems?