Writing from a rest home where he's recuperating from some illness or breakdown, Holden Caulfield says he'll tell the story of what happened to him just before the previous Christmas.
Holden's story begins at Pencey Prep on the day of the big football game. Instead of going to the game, Holden, who has just been expelled for failing four of his five classes, visits Mr. Spencer, his history teacher. Mr. Spencer lectures Holden about playing by the rules and thinking about his future. Holden pretends to agree with what he hears, but actually thinks Mr. Spencer is a "phony." Back in his dorm room, Robert Ackley, Holden's irritating neighbor, interrupts Holden as he tries to read, and Ward Stradlater, Holden's conceited and good-looking roommate heads out for a date with Jane Gallagher, a girl Holden knows and likes. Before he leaves, Stradlater asks Holden to write an English composition for him while he's away. Holden writes about his dead brother Allie's baseball mitt. When Stradlater returns, he says that the essay isn't on topic, and refuses to reveal the details of his date. Holden attacks and insults him. Stradlater punches Holden in the nose.
Holden decides to leave Pencey early. He takes a train to New York and rents a room at the Edmont Hotel. He soon feels lonely and depressed and starts acting strangely. He wears a red hunting cap everywhere he goes, asks cab drivers what happens to the ducks in the central park lagoon during the winter, and wanders around from the Hotel lounge to another bar trying to pick up women whom he claims to hate. Back at his hotel, the elevator man, Maurice, offers him a prostitute for $5. Holden agrees, but is so uncomfortable when she arrives he says he can't have sex because of recent surgery. She demands $10. When he refuses, she returns with Maurice. Maurice punches Holden in the stomach while she takes another five dollars.
The next morning, Holden makes a date with a girl he knows named Sally Hayes. He then wanders around town, and hears a boy singing a song while coming out of church: "If a body catch a body coming through the rye." Hoping to find his younger sister, Phoebe, Holden walks all the way to the Museum of Natural History, which he loves for its unchanging exhibits. But he decides not to enter the museum, and takes a cab to meet Sally Hayes instead.
The date does not go well. The play they see annoys Holden, as does the fact that Sally talks to a boy Holden thinks is phony. After going ice-skating, Holden begins to talk about everything he hates, and asks Sally to run away with him to a cabin in New England. She refuses and asks him to stop shouting. He insults her, makes her cry, and leaves. Later that night, Holden walks to Central Park to look at the ducks in the lagoon. There are no ducks, it's freezing, and he imagines he might die, which he knows would make Phoebe miserable. He decides to go home to see her.
Holden sneaks into his family's apartment, wakes Phoebe, and tells her he's leaving to go live on a ranch in Colorado. Phoebe realizes Holden has been expelled, and asks him what he wants to be in his life. Holden says he'd like to be a catcher in the rye, who rescues children by catching them before they fall off a steep cliff at the edge of a giant rye field. Holden then goes to visit Mr. Antolini, his favorite former teacher. Mr. Antolini warns Holden that he's headed for a "terrible fall" and tries to convince him to be less rigid and judgmental. Holden listens, but is too tired and falls asleep. He wakes when he feels Mr. Antolini's hand stroking his head. He thinks Mr. Antolini is doing something perverted and leaves.
Holden decides to say goodbye to Phoebe before heading west. He meets her at the Museum of Art, where she begs him to take her with him. He refuses, and then promises that he won't go either. He takes her to the zoo, where he watches her ride the carousel. Phoebe gives Holden back his red hunting hat, which protects him from the rain that has just started to fall.
Holden's story shifts back to the rest home, where he now wishes he hadn't told so many people his story, because it only makes him miss the people he tells about.