In this tense police thriller, Cheung Sung-Bong — a disciplined Senior Inspector — sets out to track down Yau Kong-Ngo and his former team after a brutal ambush during a major drugs bust against Wong Kwun. Yau and his crew finish Wong Kwun and steal the drugs, nursing a vow of revenge against Cheung and the entire police department for imprisoning them on charges tied to beating Coke to death during the disappearance of Fok Siu-tong, a bank tycoon who owns HK Fortune Banking.
To unravel the scheme, Cheung and his team raid nightclubs to learn who sold the drugs that led to Wong Kwun's operation. They identify a drug dealer named Guai Guai and move to capture him, but Guai dies as he tries to escape.
On a personal note, Chu Yuk-ming strangles his girlfriend Mei-you during a date after discovering she is cheating. The brutal act becomes a thread that Cheung later follows, helping him connect the case to Yau Kong-Ngo’s circle.
Wong Kwun's watch is found on Mei-you's body, and Cheung realizes that Chu had stolen the watch, pointing to Yau Kong-Ngo's involvement in Wong Kwun's death. This clue pushes Cheung to intensify the pursuit and tighten the net around the conspirators.
Cheung tracks Chu, and a chase ensues, during which one of Yau's teammates is arrested by the police. The investigation widens as Cheung links the string of violent acts back to the former inspector and his cohort, revealing a coordinated plan that threatens more than just the drug trade.
Yau kills Chu to cover his tracks, and he along with Mok Yik-chuen soon arrives at the police station to file a complaint about his other teammate Chiu Chi-Keung's disappearance. The move signals a chilling level of control and desperation within the group, as they try to erase another link in the chain.
The police find Chiu's body and learn that Yau strapped Cheung's former superior Sze-to Kit with a timed collar bomb and sent him to hold Cheung's pregnant wife Anna Lam hostage. The grisly detail underscores the personal stakes Cheung faces as he pursues the truth.
Cheung manages to rescue Anna, but Kit dies in an explosion, a casualty in the escalating war between the police and the rogue unit. Yau, Wah, and Mok are released due to lack of evidence, where they form a plan to rob HK Fortune Banking, demonstrating their willingness to risk everything to settle the score.
Cheung soon learns about their plan and heads to HK Fortune Banking with his team. Yau and his teammates execute the bank heist and shoot Fok Siu-tong as retribution for the years of imprisonment and the bloodshed that followed.
Cheung locates Yau and his crew, leading to a tense, high-stakes chase. The criminals are killed one by one as they try to flee, culminating in a climactic confrontation in a church where the police close in. Cornered and with the law bearing down, Yau chooses a final, fatal act and kills himself by falling on an exposed rebar rather than surrendering, while Cheung walks away, bearing the weight of the case and its costs.
