As the movie opens, a doctor informs Donnelly (Gleeson) that his wife died at 3 o'clock in the morning. He brings the man to his wife's bedside to say his last goodbye, excusing himself as he's unusually busy: there'd been two cot deaths, and a woman shot so brutally by her son "she had no head left on her". Donnelly spends a few last moments talking awkwardly to his wife and brings her a photo of 'David', their pet rabbit.
Donnelly goes home on the train. He sits opposite a chain-smoking kid (Conroy), who reveals himself to be a manic foul-mouth. In his forlorn state, Donnelly tolerates the kid, allowing himself to be engaged in some inane conversations. Less accepting of the kid's abrasive manners are a couple sitting across the aisle. After some animated exchanges, the kid leaves to get something from the buffet cart. At this time, Donnelly inquires, and finds out that the couple had just lost their son from a cot death.
The kid comes back after the couple had left their seats. Donnelly tells the kid of the baby's death. The kid seems surprised, and immediately asks, "Did they kill 'it'?". When Donnelly explains that it was 'cot death', the kid asserts that they must have "banged it on something". Upon the couple's return, things heat up again. The two almost come to blows, but Donnelly steps in.
Donnelly goes to the buffet cart to get a drink. The man comes out to get tea and engages Donnelly in a brief conversation. With her husband gone, the woman is left alone with the kid, who quickly moves over to harass her as she clutches a picture of her dead baby. He accuses her of "bang[ing] it on something", because the baby was "ugly". Aghast, the woman steps on the table to get away from him, only to trip, fall, and tear the photo. Moments later, the kid, back in his own seat, is startled by a thump at the window; the woman had thrown herself out of the train. He goes to investigate, to find an open gate, and the torn picture of the baby on the floor.
Donnelly and the husband come back. The kid nonchalantly informs the husband that his wife has jumped off the train, and is "dripping down the half of it". The man takes this as a joke, and sets out to look for her. When Donnelly turns to see the blood on the window, he pulls the emergency stop. The police arrive and the man learns of his wife's suicide. Donnelly and the kid are questioned by a policeman, who asks the kid: "Do I know you from somewhere?". As the train departs, the policeman sees the kid wildly waving goodbye, and realises that the kid is someone they want. He orders the train stopped, "and tell the boys to get the guns out".
On their way again, the kid tries to get Donnelly to take his side. When he gets no sympathy, the kid reveals that HIS mother was murdered last night, but he's not mourning. Donnelly tells the kid that his wife just died as well, and begins to weep. The kid again presses Donnelly with his "deadly" story of a cow with trapped wind. Donnelly capitulates, and the kid tells his 'true' story, which is so bizarre that Donnelly can't help but laugh. "Best day of me fucking life – that cow exploding," the kid concludes.
As the train pulls into the station, Donnelly notices armed cops everywhere. He realises that the kid is responsible for the murder to which the doctor alluded in the beginning. A shootout between the kid and the cops ensues, which leaves the kid mortally wounded. His last words are regrets that he didn't even hit one policeman. The kid dies as Donnelly cradles him. He then takes one of the kid's six shooters and hides it in his coat.
At home, Donnelly prepares to kill himself. He looks in the gun which contains two bullets. As he is about to shoot himself, he hears scratching sounds from David, his wife's pet rabbit. He takes David in his lap, and tells the rabbit: "I'll be following you shortly", before shooting it in the head. Moving the gun to his own head, Donnelly fumbles and drops it, accidentally discharging its last bullet. He looks at the smoking six shooter, then at the dead rabbit in his arms. He sighs, looks skyward and moans, "Oh Jesus; what a fuckin day."In 2004, the film won as Best First Short by an Irish Director at the Cork International Film Festival and the Festival Prize as Best Irish Short at the Foyle Film Festival.
In 2005, it was nominated for the Best Short Film BAFTA Film Award and won the Best British Short British Independent Film Award and the IFTA Award as Best Short Fiction, where it was also nominated for Breakthrough Talent (Martin McDonagh – writer/director).
In 2006, it was nominated for and won the Academy Award for Live Action Short Film, as well as the Audience Prize at the Leuven International Short Film Festival.