Lehiff (Colin Farrell) is smooth-talking an attractive shop assistant (Kerry Condon) talking about love. Suddenly, his tone changes. He hits her and steals some money from the till.
John (Cillian Murphy) splits up with Deirdre (Kelly Macdonald) but later he repents and says he only wanted to put her to the test. Soon she goes out with an older man. John has a dead-end job at a supermarket, and the audience can see he dislikes his boss, Mr Henderson (Owen Roe).
Jerry Lynch (Colm Meany) is a tough cop who threatens Lehiff and pees on him. Jerry is going to be the protagonist of a documentary about his job.
Sam (Michael McElhatton) also leaves Noeleen (Deirdre O'Kane) because he has just started a relationship with Deirdre. Soon afterwards, Sally (Shirley Henderson) and her mother meet Sam and Deirdre as a couple, but Sally completely rejects them and says so aloud, leaving the three of them speechless. Danny the bus driver, (Donagh Deeney) gets distracted because of the conversation between Sally and her mother on the bus. They get off the bus and five seconds after, the bus gets wrecked. Danny is suspended from his job, although he alleges that a boy threw a stone at the front mirror and that it wasn't his fault. Management doesn't believe him.
Oscar (David Wilmot) goes to a sex shop to ask for some porn videos - questioning the manager (Tom Murphy) in a good-for-laughs scene and then jerking off in the privacy of his home.
John pukes in front of Mr Henderson on purpose. He gives him the last notice: either he changes or he'll be sacked. Oscar and John go to a disco for older people. Noeleen and John seem to hit it off, the same as Oscar and Maura (Ger Ryan), who is Sally's mother. Oscar and Maura's relationship goes well, especially on the sexual side at the beginning. She likes hitting him a bit in the heat of passion. However, Oscar breaks up with her because she hits him.
Danny speaks to Lehiff, who suffered a car accident in a stolen car because a boy had thrown a stone at him while he was driving. Lehiff proposes a bank robbery, and they also tell John. John tells Oscar, who wants to have nothing to do with it. They argue on the supermarket shop floor, so Mr Henderson dismisses John for good.
Sally and Maura are interviewed because of the bus accident and the boy throws an egg at Maura's head and another at the camera. Sally feels ugly, until she and Oscar hit it off.
Masked and armed, John, Lehiff and Danny break into Deirdre's home while she's with Sam. Sam is going to give John and Danny the money while Lehiff stays at Deirdre's with her as a hostage. Sam and Deirdre agree, but everything turns out badly when crazy Noeleen appears and beats Sam up. The police appear to stop the quarrelling couple and John and Danny run away. On the way to Deirdre's, Danny tells John to let him out. He has seen red-hooded biker boy Philip (Taylor Molloy), the boy who threw a stone at the bus. John runs to Deirdre, and sees she's been hit by Lehiff, so John and Lehiff also fight and Lehiff has to leave.
Lehiff goes to meet the boy, Jerry, his journalist friend and the cameraman who is following him everywhere, and Danny in his car following Philip. Danny teeters on the edge of a sunken canal due to Philip. Lehiff shoots Jerry, and the journalist who has followed him everywhere kills Lehiff.
Jerry is well, and tells his friend not to release the original film, as all's well which ends well. Lehiff is dead, and Danny has a wheelchair race at the pub. Sally and Oscar are together, and John and Deirdre make amends.
Mr Henderson takes a holiday. He's obsessed with John's lack of acknowledgement of his managerial role. Philip appears once again, throws a stone at him while driving causing another road accident. Noeleen and John also reconcile, but she is much more domineering, - she won't put up with any nonsense from him any more.