The novel begins at the scene of the abattoir, where Cal's father Shamie works. Cal is there to get some cigarettes from Shamie. He hates the smell of the place and has recently rejected a job that Shamie got him because he is too squeamish. Cal goes home and smokes, plays guitar, and wallows in his usual self-contempt. He is on the dole, or unemployment, and goes to cash one of his checks. After, he visits the town library where he notices a new clerk working there; he overhears that her name is Marcella, which catches his attention. When Cal walks home, he always feels defensive as one of the few Catholics in a Protestant neighborhood. We learn that Cal has had some involvement in the "movement," or the IRA, but prefers to stay out of it all.
At dinner that night, Shamie and Cal talk about the new clerk at the library. Shamie confirms that it is Marcella Morton, a recent widow—a fact which sends Cal into another spiral of self-hatred, although as readers we are not shown why exactly. Shamie tells Cal that Crilly, a former schoolmate of Cal who also works at the abattoir, wishes for Cal to visit him that night. Crilly is Cal's connection with the movement and regularly pressures Cal to become more involved, despite Cal's protests. At his house, Crilly is there with a man named Finbar Skeffington and they convince Cal to start working as a driver for them again.
Cal begins visiting the library to observe Marcella and even follow her some nights when she leaves her shift. One night, he sees her drop a bag of groceries and uses this as an opportunity to make small talk with her. Later, Cal finds a note from the local Loyalist gang, called the UVF, that threatens to burn his house down if he and Shamie don't leave. As a result, Shamie takes out his gun to keep by him while he sleeps. This gun was given to them by Crilly after Cal started helping out with the movement.
Cal attends service at the Catholic church one Sunday where he sees Marcella there; he is surprised to learn she is also Catholic. He then goes to a Catholic town 60 miles away to watch a soccer game, where he runs into Skeffington, who again asks him about his participation in the movement. Later that week, Cal and Shamie work on a neighbor's property cutting down an old tree. Cal gets the idea to take a pile of chopped wood and bring it to the Morton farm, where he knows Marcella lives. He is disappointed when her mother-in-law, Mrs. Morton, answers the door instead. She accepts the wood and offers Cal a job harvesting potatoes for the next day. While in their house, Cal hears a man coughing violently and Mrs. Morton tells him that it is her husband, who is not well.
The job is grueling and repetitive but Cal is somewhat grateful to have something to occupy his time and he is able to spot Marcella, and her young daughter Lucy, a few times. After a few days helping out on the Mortons' farm, Mrs. Morton offers Cal a regular job and Cal accepts. Meanwhile, one night Cal narrowly escapes being assaulted by a few UVF members. The incident disturbs him and Shamie and makes him feel more willing to working with Crilly. He assists Crilly as a driver one night on a robbery.
At his new job on the farm, Cal must work under a Protestant man named Cyril Dunlop, who, despite being an acquaintance of Shamie, enjoys bossing Cal around. Cal is disappointed that he rarely gets to see Marcella. He goes to the library one day after work to see Marcella and he approaches her for a lighthearted conversation. When he walks home that night, he finds that his house has been set on fire by the UVF. He and his father are devastated and go to stay with a cousin, Dermot Ryan. Cal remembers, however, that he has left his gun in the house. Worried the police will find it, he races back into the charred house to grab it. Most of their other possessions have been destroyed.
Cal decides he will secretly stay in an old cottage that is on the Mortons' property without telling them. He goes there each day after work and must be quiet and not use any lights, so the Mortons do not find out. From here, he can spy more easily on Marcella. While in the cottage, he remembers back to the day, a year earlier, when he was a driver for Crilly. They were sent on a mission to murder Robert Morton, the husband of Marcella. Crilly shot Robert fatally and also injured his father, Mr. Morton. Cal knew the night that it happened that his life would never be the same. With this revelation, we better understand Cal's obsession with Marcella and his constant sense of guilt.
Cal is discovered one night in the cottage by the police. The Mortons called the police after noticing that someone was there, although they didn't know it was Cal. Mrs. Morton is furious at Cal and threatens to fire him. She is prone to becoming upset because of the trauma she endured after the death of her son. Marcella calms her down and convinces her to let Cal stay in the cottage.
The next day, Marcella helps Cal spruce up the cottage and they have tea, where they talk deeply for the first time. Marcella reveals that she is from an Italian Catholic family and moved to Ireland to be with Robert. At the mention of Robert, Cal feels awkward and tries to change the subject. Marcella and Cal start to spend more time together; she drives him to Mass on Sundays, although they sit in separate pews. From their conversations, Cal learns that Marcella feels trapped and bored living with her in-laws. They go blackberry picking one afternoon with Lucy, which is both enjoyable and terrible for Cal. He is happy to get closer to her, but also miserable as he knows that his secret means they can never be together.
Cal finally goes to visit his father and finds him in a terrible state. Since the fire, he has become very depressed. Cal worries about him and urges him to go to the doctor. He also reminds him to not tell Crilly or anyone else about his new residence, as Cal wants to avoid IRA matters completely.
One week, Mrs. and Mr. Morton go away and Cal is left on the property alone with Marcella. She cooks them a fancy dinner one night and Cal hopes this can be an opportunity to take their relationship further. When he tries to kiss her, Marcella pulls back and explains that as a widow she is not open to a romance with him. Cal, frustrated, leaves and tries to avoid her for the next few days. One snowy evening right before the Mortons return, Marcella appears at Cal's cottage to apologize and explain her difficulty in opening up again after Robert's death. They end up having sex several times. Cal is elated and somewhat in shock to finally be with the woman he's been obsessing over for months. He is also in despair knowing that they don't have a real future together.
It is a few days from Christmas and Cal goes to buy gifts for his father and Marcella. When he brings a present to Shamie, he learns from Dermot that Shamie was in such a bad state that he has been put in a psychiatric hospital. Cal then goes to the library to see Marcella, who is not there, and instead runs into Crilly. Crilly is there to plant a bomb in the bookshelves. He insists Cal come with him to see Skeffington, as they have both wondered where he has been.
At Crilly's house, the men accuse Crilly of being a traitor to the cause. Before they can talk more, however, there is a knock on the door. It is the police. The men escape out the back door to run away. Cal is able to get away but the police catch up to Crilly and Skeffington and arrest them. Cal goes to anonymously report the bomb in the library and then goes back to the cottage. There, he spends time with Marcella, giving her her gifts and sleeping together again. He has a feeling that something bad might happen and that Crilly probably gave his name to the authorities. Sure enough, the next morning Cal is arrested by the police and he feels relieved that someone is finally punishing him in the way he deserves.
