The film begins with Ray explaining that he has killed someone in London. He's a hitman. Ray hears back from his superior, Harry, that he needs to get out of London. He's told to go to Bruges with his mentor Ken. Ray doesn't even know where Bruges is, and believes it to be a horrible place to have to hold up while they await further instruction.
While in Bruges they come across a film set where a dwarf named Jimmy is acting in a scene. Ray finds this quite humorous, much to the dislike of the actor. While on set, he meets Chloe who is a production assistant who also deals drugs. Ray's attracted to her so they go on a date where Ray ends up getting into an argument with a couple that turns into Ray knocking them both out in the restaurant. Chloe and Ray leave their date spot and return to her apartment and while they are beginning to have sex her ex-boyfriend comes in with a gun. Not knowing that Ray can handle himself in these types of violent situations the ex-boyfriend finds himself disarmed and Ray, with the man's gun--which is filled with blanks--fires shots near his face causing him to go blind in one eye. Ray learns that Chloe and her boyfriend rob tourists and he was simply a mark for them that went wrong.
Ray finds himself having a drink with the dwarf from the film and they carry on through the night doing drugs with prostitutes. Meanwhile, Ken is back at the hotel where he gets a call from Harry that he's to kill Ray. When Ray killed the man in London, who was a priest, he also killed a young boy by accident as the bullet went through the priest and into the boy. For this, Harry wants him dead as he believes killing a child is unforgivable.
Ken approaches Ray in a park where he is set to kill him when he notices that Ray has a gun and is preparing to take his own life. Ray is overwhelmed by grief for killing the boy and Ken stops him from committing suicide. Ken tells Ray of Harry's order to kill him and demands he get out of Bruges, he even gives him money, takes his gun and puts him on a train. Ken tells Harry directly that he let Ray go and this causes Harry to come to Bruges in outrage for Ken's betrayal.
On the train, Ray is spotted by the couple he attacked in the restaurant on his date and the police arrest him and take him back to Bruges. Once there Harry is after him, and this is after Harry has shot Ken in the leg and then in the neck while Ken was attempting to disarm him. Ken climbs to the top of the tower in the town and jumps in order to warn Ray that Harry is there to kill him. He sacrifices his own life so that the younger man may live.
Harry is now chasing down Ray through the streets of Bruges and he finally hits Ray with bullets. But in doing so he has also killed Jimmy, the dwarf, who was filming a scene and dressed as a school boy. Not knowing that Jimmy was a grown man, Harry kills himself, believing he's killed a child. Ray is taken away by an ambulance as Chloe and her boyfriend watch. Ray believes that hell may just be an eternity in Bruges. As the film ends, he narrates that he hopes he won't die.