Eilis Lacey, a young woman living in Enniscorthy, Ireland, has never left home. She lives with her mother and her older sister, Rose, who is a well-liked and confident woman. Unlike Rose, who works in an office in town, Eilis doesn’t have a job, though she’s studying to become a bookkeeper. Unfortunately, though, there are no positions available, so she accepts a job working at a grocery store owned by a pompous social climber named Miss Kelly. Each Sunday, she works at the cash register while Miss Kelly talks to her customers, treating each person differently depending upon their social status. Over dinner, Eilis tells her mother and Rose about her day, impersonating Miss Kelly and making them laugh. Her mother and Rose find these impressions especially funny because they dislike Miss Kelly, since she once snubbed Rose when she came into the store. For this reason, Rose dislikes that Eilis is working in the shop, so she arranges with a priest named Father Flood—who is Irish but lives in Brooklyn, New York—to give Eilis an opportunity to migrate to America.
Father Flood and Rose work together to help Eilis prepare for her move to Brooklyn, where she’ll live and work in Father Flood’s parish. In the days leading up to her departure, she spends time with her friend Nancy, who is in the beginning stages of a relationship with the town’s most sought-after bachelor, George Sheridan. Eilis even accompanies Nancy to a local dance so that Nancy can see George. As Nancy and George dance, Eilis stands awkwardly next to George’s friend Jim Farrell, who snubs her. Fortunately, none of this really matters to Eilis when she starts preparing to leave for America. At the same time, though, she has reservations about her departure. One night, Rose helps her pack and insists upon giving her jewelry, and Eilis realizes that Rose should be the one leaving, not her. After all, Rose would do very well in America. Worse, Eilis suddenly understands that Rose is making a sacrifice by arranging for her to go to Brooklyn, since this means that Rose herself will have to continue living with their mother and therefore won’t ever marry. Understanding the significance of her departure, then, Eilis wishes she could admit that she doesn’t even want to go, but she realizes this will only upset both Rose and her mother, who have decided to do everything they can to give her this opportunity. Accordingly, she decides not to say anything at all about her misgivings.
Eilis leaves Enniscorthy and meets her brother, Jack, in Liverpool, England, where they spend the day together before she boards an ocean liner bound for America. As they catch up, Jack admits that he felt quite sad when he first left home to work in Birmingham, though he never mentioned this in any of his letters. Thankfully, though, this feeling soon passed. Eilis considers this later when she settles into her third-class cabin on the ocean liner, realizing that she will have nobody to help her through any homesickness in Brooklyn. As she considers this, a woman named Georgina enters the cabin. Elegant but brash, Georgina has been on multiple transatlantic voyages and knows how to sneak into the first-class lounge, but Eilis politely says she’d prefer to stay in the third-class quarters.
That night, Eilis gets seasick while Georgina remains in first class. Worse, she can’t access the bathroom that her room shares with another room, since her neighbors locked it, so she throws up all over the cabin and in the hallway. The next day, Georgina returns and informs Eilis that everyone on the boat is sick. The boat, she says, is moving through a terrible storm that will last for several more days. She says there’s nothing they can do to keep themselves from vomiting, but she promises the discomfort will eventually subside. All Eilis has to do is wait it out.
In Brooklyn, Eilis moves into a house owned by an Irish woman in Father Flood’s parish named Mrs. Kehoe. Her roommates include two older Irish women named Miss McAdam and Sheila Heffernan, along with two younger women named Diana and Patty. There is also a woman named Miss Keegan, who lives in the basement and rarely speaks. At first, Eilis is too busy to think very much about Ireland, especially since Father Flood gets her a job at a department store called Bartocci’s, where she works on the sales floor and has to make a constant effort to look happy, lest her supervisor, Miss Fortini, reprimand her for not having the right attitude. Eventually, though, she receives letters from her mother, Rose, and Jack, all of which come at the same time. She reads them one by one and suddenly feels a staggering sense of homesickness, recalling what Jack said about feeling sad when he first left home, and she contemplates writing to him but ultimately determines that he’s too far away to help. In fact, she decides not to say anything about her sadness to any of her family members, not wanting to worry them.
Feeling alone and detached from the world, Eilis tries to hide her sorrow at work, but Miss Fortini notices and tells her to follow her downstairs. Miss Fortini gathers that Eilis misses her family and home, since she’s never been out of Ireland before. She then calls Father Flood and Miss Bartocci, the owner’s daughter. In turn, Miss Bartocci talks to Mr. Bartocci, who says that Eilis can go home for the day. Shortly thereafter, Father Flood comes to Bartocci’s and talks to Eilis, telling her that he should have checked in on her and that it’s understandable for her to be sad. Everyone, he says, experiences homesickness, but he assures her it will pass, especially if she distracts herself. He then enrolls her in night classes at Brooklyn College, where she takes the courses necessary to become a certified bookkeeper.
As Eilis focuses on her studies in the ensuing months, her homesickness subsides. Around this time, Father Flood starts hosting dances at the church, and Eilis has no choice but to go. After attending the first one with Miss McAdam and Sheila, she pretends to be sick for the second one. On the night of the third dance, Mrs. Kehoe asks Eilis to take Dolores, a new tenant whom everyone in the house dislikes because she pays part of her rent by cleaning for Mrs. Kehoe. Unsure of how she could possibly decline, Eilis agrees to take Dolores, but she abandons her when a young man asks her to dance. His name is Tony, and it becomes quite obvious that he’s interested in Eilis, as he admits that he looked for her the previous week but couldn’t find her. They dance the entire night—getting close for the slow songs—and then he walks her home, admitting that he’s not actually Irish, but Italian. Before they part, they make plans to meet for dinner before the dance the following week.
Slowly but surely, Eilis and Tony’s relationship develops. Unlike Eilis, he is open and willing to express his feelings, eagerly telling her how much he likes her. As their relationship progresses, Eilis writes private letters to Rose about him, responding to her sister’s questions, though she dislikes having to tell her that Tony is a plumber. Meanwhile, she keeps the news of her relationship a secret from her mother. One night, Father Flood goes out of his way to introduce himself to Tony, and Eilis can tell that Rose has asked him to do this. Thankfully, though, Father Flood takes an immediate liking to him, and Eilis reflects upon the fact that it’s not always possible to judge a person’s character based on their profession—something she thinks Rose should learn. Despite how smitten she is with Tony, though, she’s quite alarmed when he starts saying that he loves her and casually mentions having children with her someday. At first, she doesn’t respond, but she eventually tells him that she loves him too, though she isn’t ready to talk about having children.
As Eilis nears the end of her second year in Brooklyn, she receives news that Rose has died in her sleep. When she calls home, her mother explains that Rose had a heart condition that she kept secret. In the coming days, Eilis feels at a loss, knowing that she should return home to keep her mother company but not wanting to leave her life in Brooklyn. Around this time, she sneaks Tony into her basement bedroom because she’s too sad to be alone, and they end up having sex. Afterwards, she can tell that Mrs. Kehoe heard them and that she must have told Father Flood, who starts avoiding her. To make things right, then, she visits Father Flood and—because she doesn’t know what to talk about—tells him that she wants to go home to visit her mother. Apparently deciding to forgive her, he helps her convince Miss Fortini to give her a month off from work.
When Eilis tells Tony that she’s returning to Ireland, he asks her to marry him, insisting that they can do it secretly and then have an actual ceremony when she returns. Hesitant at first, she agrees, and they go through with the plan just before she departs. When she arrives in Ireland, though, she fails to tell her mother about Tony. Instead, she focuses on helping her write thank-you cards to the many people who paid their respects after Rose died. Later, she sees her friend Nancy, who tells her that she’s getting married to George in several weeks and that Eilis’s mother said that Eilis would be attending. Thinking there will be no harm in delaying her return to Brooklyn, Eilis agrees to go to the wedding.
As the wedding approaches, Eilis starts spending time with Nancy, George, and Jim, who has taken an interest in her. At first, their rapport is friendly and innocent, but they soon develop a relationship, and Eilis even kisses Jim after a dance one night. Consequently, everyone in town gets excited about the prospect of Eilis marrying Jim, since nobody knows that she’s already married to Tony, to whom she has stopped writing letters. The wedding comes and goes, and still Eilis puts off buying a ticket back to America. Finally, though, Miss Kelly calls her to her store and tells her that Mrs. Kehoe is her cousin and that they stay in touch, passing news back and forth. She explains that she told Mrs. Kehoe that Eilis has started seeing Jim. She then implies that Mrs. Kehoe told her about Tony, so Eilis rushes out of the grocery store, buys a return ticket to Brooklyn, and tells her mother that she’s married. The next morning, she drops a letter at Jim’s door explaining that she had to leave, and sets off for America once again.
