23-year-old Neil Klugman lives with his Aunt Gladys and Uncle Max in a working class Jewish neighborhood in Newark, New Jersey in the late 1950s. One summer day, Neil is invited to the Green Lane Country Club in the suburb of Short Hills, New Jersey by his cousin Doris; there, he meets 21-year-old Brenda Patimkin. Brenda is beautiful, with short auburn hair, and she asks Neil to hold her glasses for her while she dives into the pool. Smitten, Neil calls her that night and introduces himself, asking if they can meet up. She agrees. Neil drives to meet Brenda back at the club, where she is playing tennis with a friend. After she wins her match, she and Neil walk and sit together, getting to know one another. She tells him that she goes to school “in Boston” (meaning Radcliffe, Harvard’s sister college) and talks about the fact that she has had her nose fixed because it used to be “bumpy.” After they speak some more, Neil kisses her for the first time.
Over the next week, Brenda and Neil continue to meet at the club. They start to deepen their feelings for one another as they play in the pool together. Neil meets Brenda’s athletic older brother Ron and also goes over to her home in Short Hills for dinner, where he meets her 10-year-old sister Julie and her parents, Mr. and Mrs. Patimkin. He notes that the Patimkins are very wealthy and he feels intimidated at the dinner.
Neil also works at the Newark public library, and just as he starts his relationship with Brenda, a small African American boy begins coming in every day to look at a book of Paul Gauguin’s artwork. The boy particularly likes the images of the Tahitian women, and he dreams of having a peaceful life like the one depicted. Neil understands his enthusiasm for the images, and he thinks that Short Hills is just as idyllic.
One night, Neil arrives at the Patimkins’ just as they are driving Ron to the airport—he is going to visit his girlfriend Harriet in Milwaukee. Brenda asks Neil to stay and watch Julie. Neil at first wants very little to do with Julie and instead explores the house, eating fruit out of the Patimkins’ refrigerator in the basement. When Julie catches him, he agrees to play ping pong with her. He refuses to go easy on her, however, and she cries and storms off when he is one point away from winning. That night, Neil and Brenda make love for the first time in the Patimkins’ TV room after everyone else has gone to sleep, and Neil thinks that it is as sweet as winning the match against Julie would have been.
Over the next week and a half, the young boy returns to look at the Gauguin book in the library, and when an older white man comes in to check the same book out, Neil lies and says it is on hold so that the boy can continue to look at it. Meanwhile, Neil continues to see Brenda every night. One evening, they go to the club as it is closing, and Brenda suggests they play a game. One person closes their eyes and waits as the other person does laps in the pool, then comes back and gives them a very wet kiss. Neil grows worried during the game that Brenda will simply leave him. When she returns after staying away a particularly long time, he clings to her and tells her that he loves her.
The summer continues, and Neil and Brenda do many different activities together: swimming, walking, driving, attending basketball games, dancing, and making love almost every night. One day, Brenda suggests to her father that Neil stay for a week at the end of August, and Mr. Patimkin agrees. When Neil tells Aunt Gladys about this, she is skeptical that a Jewish family would live in Short Hills, but she agrees to let him go.
On Neil’s last day of work before his vacation, the older white man comes back to ask about the Gauguin book. Neil tries to cover for the little boy again, rudely turning the older man away. As Neil drives to Short Hills that evening, he worries that the old man might complain and that he’d lose his job, but he realizes that he doesn’t want the library to be his life anyway.
When Neil arrives, Julie tells him that Ron (who has returned from Milwaukee) is getting married to Harriet in two weeks, on Labor Day, and so the Patimkins immediately launch into wedding planning. Neil unpacks in the guest bedroom, but he and Brenda make a plan for Neil to sleep in her room and then sneak back into the guest bedroom in the morning. While Neil unpacks, he hears Brenda and Mrs. Patimkin argue over the fact that they have too much company, and Mrs. Patimkin accuses Brenda of being lazy. Brenda returns to Neil, upset, but she assures him that Mrs. Patimkin simply doesn’t like Brenda and is stressed about Ron’s wedding. Brenda also shows Neil a room off of the guest bedroom in which the Patimkins have stored all of their old furniture from their old house in Newark. She tells him that Mr. Patimkin hid $300 in there for her if she needed it, but when she can’t find the money, she tells Neil to make love to her on their old sofa.
The week passes, and Brenda and Neil race together on the track at the high school and continue their routines, with him sneaking into and out of her room each night. Neil starts to realize that he is looking more and more like Brenda in the way he dresses and acts. Brenda then arranges for Neil to stay another week, straight through to Ron’s wedding (which is the day before she returns to school). When Harriet arrives, Neil starts to think about marrying Brenda, but he is worried she’ll say no. He instead suggests to Brenda that she get a diaphragm, but she is hesitant because she doesn’t want to have to lie that she is married to get one. He is upset, thinking that he would do a lot of things for her, but that she doesn’t do anything for him just because he asks. She walks away, crying at the implication that she doesn’t care for him enough to get a diaphragm.
The next day, Brenda and Harriet go into the city to buy dresses for the wedding, while Neil does an errand for Mrs. Patimkin. He goes to Mr. Patimkin’s work (he runs a kitchen and sink business) and picks up silver patterns for the wedding. There, Mr. Patimkin talks to Neil about his children, saying that they are “goyim” (non-Jewish people). Mr. Patimkin says that when he got married, they only had cheap silverware, while his kids have to eat off of gold—though Neil notes that he says this with pride rather than consternation. When Neil returns to the house, Brenda and Harriet are back. Brenda tells him that she called the Margaret Sanger Clinic in New York to get a diaphragm, but they asked her if she was married and she hung up. When Neil presses her that they can go to a doctor together, she finally relents.
Three days before Ron’s wedding, Neil and Brenda go to New York City so that Brenda can get a diaphragm from the doctor, even though she’s still visibly upset about the idea. While she goes into the office, Neil goes to a church and prays, wondering if he really loves Brenda or if he’s rushing into things. When Brenda returns, she says she’s wearing her diaphragm. Neil tells her that he loves her.
Over the weekend, Neil and Brenda barely see each other in the chaos of wedding preparations. The night before the wedding, Ron plays a record for Neil, which has his school song on it (he went to Ohio State University) and highlights from his senior year, including the announcement of a basketball game in which he played. The record ends with a voice saying, “goodbye, Columbus,” and Ron hums along with the record, nostalgic.
The wedding is full of drunken cheer, and Neil and Brenda dance during the reception. Neil also speaks to Mr. Patimkin’s half-brother Leo, who is resentful of Mr. Patimkin’s vast wealth while Leo (a traveling lightbulb salesman) has so little. He tells Neil that if he plays his cards right and marries Brenda, Neil can have some of that wealth. Mr. Patimkin also implies to Neil at the reception that if he and Brenda wanted to get married, they would have Mr. Patimkin’s blessing and Neil could join the business. At the end of the night, Neil finds Brenda asleep in the lobby of the hotel, and Neil wonders if he really knows her. The next day, he drives her to the train, and Brenda returns to school.
Neil returns to the library, where his boss Mr. Scapello scolds Neil for his treatment of the older man. The Gauguin book is checked out, and Neil doesn’t see the young boy anymore. Soon after, Brenda suggests that Neil come up for the Jewish holidays to visit her, telling him that she booked a hotel room for them, and Neil agrees. Aunt Gladys is displeased that Neil will miss his parents, who are coming in from Arizona for the holidays, but Neil is insistent on visiting Brenda.
When Neil arrives in Boston, however, Brenda reveals that she left the diaphragm in her drawer and her mother found it. Her mother is heartbroken, and her father admonished her for her mistake. She doesn’t know how she could bring Neil to their home again. Neil is frustrated, thinking that Brenda left the diaphragm on purpose so that Mrs. Patimkin would find it and they’d have to break up. Brenda denies this, but both of them realize that they can’t continue their relationship. Neil leaves the hotel and thinks about how much their relationship had been built on this idea of winning and losing, and how he had likely loved her just for her beauty and wealth. Neil gets on a train back to New Jersey, and he arrives in Newark on the first day of the Jewish New Year.