The film begins with a doctor informing Donnelly (Brendan Gleeson) that his wife died. Donnelly goes to visit his wife to say goodbye (showing her a picture of their beloved pet rabbit along the way) to his wife and quickly excuses himself after the doctor tells him how busy he is because of several murders. He then swiftly goes to the train to go home, where he meets a foul-mouthed, chain-smoking kid and a couple . They talk for quite a while before the kid goes to the food cart of the train to get something to eat. The kid returns and they discuss the death of the baby (which is a "cot death"). When the couple is brought in, though, things gets heated.
Donnelly goes to the food car. But when he and the husband return, the kid informs the husband that his wife had jumped off the train and her guts were spilt all over it. The man initially takes this as a joke, but when he can't find his wife and starts to look for her, he sees her blood and guts on the train. The man pulls the emergency stop and the police investigate. But when Donnelly gets off and sees the kid oddly waving at him, he orders the train to stop again. It is then when he realizes that the kid is wanted.
The train moves on again. The kid tries to get Donnelly on his side. They talk about the deaths of the child, Donnelly's wife, and the people the doctor said at the start of the film.
When the train pulls into the station, Donnelly sees quite a few armed cops with their guns drawn at the station. He realizes that the kid was responsible for the murders the doctor told him of in the beginning and a shootout between the kid and cops ensues. The cops gravely injure the kid, but before he dies, he tells Donnelly that he regrets not hitting one cop. As the boy dies, Donnelly cradles him in his arms and takes one of his six shooters.
Donnelly returns home and prepares to kill himself. But as he goes to shoot himself, the gun falls from his hands, discharging its final bullet into a beloved pet rabbit. He looks into the sky and moans: 'Oh Jesus; what a fuckin day.'
