Triad boss Lung Eddy Ko Hung survives an assassination attempt inside a restaurant, a venue owned by Fat Cheung Wong Tin-Lam, an underboss of Lung's triad. The attack leaves one of Lung's men dead and sets off a plan to keep the boss safe at all costs.
To ensure his safety, Lung's right-hand man and brother, Frank Simon Yam, hires five bodyguards to stay close to the pair 24/7: Curtis Anthony Wong, a retired triad veteran who has traded a dangerous life for a quiet one as a hairdresser; James Lam Suet, a quiet loner and the firearms expert of the group; Roy Francis Ng Chun-Yu, a rising capo with a sharp mind and sharper reflexes; Shin Jackie Lui-Chung-Yin, Roy's quick-witted underling; and Mike Roy Cheung Yiu-Yeung, a former pimp and sharpshooter who still knows how to use a gun when needed.
An initial attempt on Lung ends quickly in tragedy when a rooftop sniper targets the cars carrying Lung and his entourage. Lung is wounded, though a bulletproof vest saves him from a fatal shot. The group fights back, and Curtis decides to stay with Lung in the car, joining James, Mike, and Shin—even though Roy hasn’t returned yet, having pursued a second attacker. Roy eventually returns in a taxi, furious, and beats up Curtis; the assault is brief, but it reaffirms the volatile dynamics within the team. The next day, Curtis makes amends by killing a criminal who harassed Roy's nightclub, signaling that the guards will act decisively when loyalty is tested.
Two more assassination attempts come and go as the five guards doggedly hunt a surviving hitman to the hideout of the attackers. After a tense gunfight, they capture the hitman alive. It becomes evident that Fat Cheung is behind the hits, and Lung sends Frank to kill him. The bodyguards finish the captured operative and, feeling a momentary sense of relief, celebrate their victory in a restaurant.
Frank hands Curtis five envelopes with pay and drops a bombshell: Shin has been having an affair with Lung's wife. Curtis agrees to handle the matter, while he and James plot to confront Shin. Curtis goes to James to borrow a gun and arranges an evening meeting with Shin. James warns Roy, and Roy is forced to confront Shin about the accusation. Shin concedes the affair, and Roy—who has authority over Shin—refuses to permit Shin’s execution. They consider sending Shin to Taiwan, but abandon the plan, fearing Frank would pursue them for their failures.
That evening, the five men reconvene in an otherwise empty restaurant to settle the matter once and for all. James leaves to ask Lung for clemency and to spare Shin's life. Upon arriving at Lung's house, he witnesses a Lung henchman kill Mrs. Lung Elaine Eca Da Silva, an act that underscores the perilous stakes and the futility of mercy in this violent world. James returns to the restaurant with a grim sense of inevitability as a Mexican standoff unfolds between the men. Curtis shoots Shin, while Roy fires his magazine—without aiming at Curtis. As they prepare to leave, Curtis hurls a blank toward James, revealing that Shin’s death was staged for Lung; Shin had escaped through the backdoor, and the ruse was meant to keep Lung fooled and safe—at least for the moment.
