Eilis has been married to Tony for two decades, and they reside in Long Island with their teenage children, Rosella and Larry. Their home is part of a compound with Tony’s brothers, Enzo and Mauro, and their families, as well as Tony’s parents. Tony works as a plumber in the family business, while Eilis clashed with Tony’s family over financial matters and chose to work for an Armenian mechanic, Mr. Narbadian, who values her skills. Eilis’ children are more independent, well-read, and politically liberal compared to their cousins. Rosella aspires to study law, but Eilis finds the proximity of the other families stifling, especially her mother-in-law Francesca’s intrusive interrogations of Rosella and Larry.
A visitor from Ireland informs Eilis that Tony has impregnated another woman while working on their home. The man refuses to raise the child with Tony’s children, planning to leave the baby on their doorstep upon its birth. Eilis is devastated and confides in no one. She lets Tony’s stew spill during dinner, prompting him and the children to clean up the mess and replace the food. In bed, Eilis confronts Tony about the situation, and his silence suggests the man is serious. He starts avoiding her, and one night, she makes it clear that she won’t care for the illegitimate child, nor will she allow it into her home. Tony reluctantly agrees, and Eilis seeks a leave of absence from work, planning to travel to Ireland for ten weeks during the baby’s birth.
Eilis receives a letter from her mother in Enniscorthy, who avoids mentioning Jim Farrell, the man she left behind to return to Tony. Eilis has sent letters and photographs to her mother monthly, but the responses have been minimal.
Francesca visits Eilis to discuss Tony’s affair and what they should do. Eilis reiterates her refusal to accept the child being raised by Tony’s family. She arranges her trip to Ireland, hoping to coincide with the baby’s birth, and makes Tony promise that neither she nor her children will ever have to see the baby. He reluctantly agrees, and Eilis informs the children about the situation. Rosella is devastated, but they will join Eilis in Ireland. Frank gives Eilis money to make her trip more comfortable.
The story shifts to Enniscorthy, where Eilis reconnects with her childhood friend Nancy, who is running a chip shop. Nancy is secretly involved with Jim Farrell, and the two plan to announce their engagement after her daughter Miriam’s wedding. Eilis spends time with her family in Ireland and learns that her elder brother, Martin, owns properties including her mother’s and her other brother Pat’s homes. Her mother is uninterested in her life in America, leaving Eilis frustrated.
One night, Eilis encounters Jim Farrell standing outside his pub. They have a brief exchange and go their separate ways. Nancy’s wedding preparations and family obligations keep Eilis busy during her stay in Ireland. At the wedding, Eilis learns from Nancy’s friend that Jim was in Cush. She doesn’t see much of him during the celebration, as Nancy is occupied as the mother of the bride.
Eilis visits Jack’s house in Cush to get away from her mother. She thinks about the timing of her sexual rediscovery with Tony, realizing that his affair revitalized their relationship. She swims in the sea and, upon emerging, spots Jim standing on the beach. He learned of her presence from Jack and an encounter with a friend of Nancy’s, who might question his visit to Cush.
Jim yearns to speak to Eilis, but he can’t sleep. He reflects on his business success and the lack of romantic fulfillment in his life. Jim drives Nancy to Dublin to shop for Miriam’s wedding, expressing his impatience to marry her.
Eilis and Jim attempt to meet for dinner and spend the night together, but they struggle to find condoms. They ultimately enjoy dinner and share the same bed without having sex. Eilis hints that her marriage is in trouble, and Jim regrets not following her to America. He expresses a desire to be with her and offers to come to the United States if she wishes.
Eilis returns to Long Island with her children. Rosella shares that Tony’s family knows about the baby, revealing that Larry accidentally disclosed the information. Eilis calls Jim but disconnects without speaking. She receives a letter from Francesca, including a photo of the baby, and it is evident that they are unaware of Eilis’ presence in Ireland.
In Cush, Eilis spends time with Jim, and they engage in a sexual relationship. She confides in Jim about her unhappiness in her marriage but requests six months to make arrangements before they can be together. Jim agrees, and they profess their love for each other, with Eilis promising not to change her mind.
Nancy arrives in Cush to find Jim and Eilis kissing. She rushes back and announces her engagement to Jim to everyone she encounters. She visits Eilis’ mother to share the news. Eilis returns to her mother’s house, and her mother reveals she booked a return flight to America for them both. Eilis also learns of Nancy’s announcement.
Eilis calls Jim’s pub, but he doesn’t answer. She worries about Jim, knowing that he is with Nancy. Jim realizes that Nancy is lying about how she learned of their relationship. He anticipates Eilis’s visit and waits for Nancy’s return.
The story concludes with unanswered questions about the futures of Eilis, Jim, and Nancy, as they navigate their complex relationships and emotions.