Carrying out orders, inexperienced hitman Ray shoots a priest during confession, but accidentally kills a young boy who is also in church. He and his mentor Ken are sent to Bruges by their employer Harry, where they are to await further instructions. Ken finds the city beautiful and relaxing, while Ray is bored and hates it.
They chance upon a film shoot involving a dwarf actor, which amuses Ray. Ray is attracted to Chloë, a local drug dealer moonlighting as a production assistant. He takes her to a restaurant, where he gets into an argument with a Canadian couple (mistaking them for Americans) and punches them. Chloë takes Ray to her apartment where they begin to have sex, but her ex-boyfriend Eirik appears and threatens Ray with a handgun. Ray effortlessly disarms the small-time criminal and fires the gun, loaded with blanks, in Eirik's face, blinding him in one eye. Chloë admits that she and Eirik rob tourists, but insists she had told Eirik that Ray was not a target. As Chloë drives Eirik to the hospital, Ray pockets the gun and helps himself to a handful of live rounds as well as Chloë's stash of drugs. He and Ken spend a debauched night with the dwarf actor, Jimmy, who takes cocaine and rants about a coming war between blacks and whites.
Harry calls Ken and orders him to kill Ray, on the principle that killing a child, even accidentally, is unforgivable. With a handgun supplied by Harry's local contact Yuri, Ken tracks Ray to a park and reluctantly prepares to kill him. Ray, however, distraught at his killing of the boy, prepares to kill himself with Eirik's loaded gun. Seeing this, Ken stops Ray, informs him of Harry's order and tells him to leave Bruges to have a fresh start. He gives Ray some money and puts him on a train to another city, while confiscating his gun to prevent a further suicide attempt. Ken reports the truth back to Harry, who immediately sets out for Bruges, furious at the insubordination. He picks up a gun at Yuri's, and Eirik, Yuri's son, learns of his intention.
Ray's train stops, and the police escort him back to Bruges for attacking the Canadians. Chloë bails him out and the two share a drink on the market square beneath the Belfry of Bruges. Harry spots Ken sitting outside a cafe. As the two have drinks, Harry boasts that if he himself had killed a child, he would have immediately taken his own life. Ken argues that Ray is trying to better himself and deserves a chance at redemption. Harry is not convinced. Ken suggests they ascend the bell tower for a shootout away from bystanders. At the top, Ken says he accepts whatever punishment Harry intends. A conflicted Harry cannot bring himself to kill Ken, so he shoots him in the leg as punishment for not killing Ray. Seeing Ray at the square, Eirik climbs the tower to inform Harry, who is helping Ken down the tower. Ken tries to disarm Harry, who shoots Ken in the neck and rushes down. Bleeding heavily, Ken drags himself back to the top of the tower and jumps into the square. Ray rushes to Ken, who warns him of Harry's arrival just before he dies.
Harry chases Ray to the hotel; Marie, the pregnant owner, refuses Harry entry, even when he draws his gun. To protect the owner and her unborn child, Harry and Ray agree to continue the chase on the canal. Ray, armed with Eirik's loaded gun, jumps onto a passing barge but drops the gun. Harry wounds Ray with a shot from a distance. Ray collapses on the street where Jimmy's film is shooting. Harry catches up and repeatedly shoots Ray. One of the bullets hits Jimmy (costumed as a schoolboy), blowing his head open. Mistakenly believing that he has killed a child, Harry, despite protest from Ray, kills himself. Ray is carried past Chloë, Marie and Eirik into an ambulance. In narration, Ray reflects on the nature of hell, speculating that it is an eternity in the city of Bruges, and recalls that he really, really hoped he would not die.
