Holden Caulfield has been expelled from Pencey Prep because he failed 4 of his 5 classes. Holden doesn't care that he got expelled because he thinks schools are just "phony" institutions run by adults. He sits atop of a hill watching the school football game; isolated from the rest of the students, who are in the stands.
Holden wants to talk to one of his favorite teachers, Mr. Spencer, so he can say his goodbyes. Rather than being sympathetic towards Holden, Mr. Spencer scolds him and tells Holden that he has to apply himself in order to be successful. Mr. Spencer's cold attitude, old age, and bumpy chest scare Holden, so he leaves as quickly as possible.
Holden's roommate, Stradlater, asks Holden to write an English composition for him while he's on a date with Jane Gallagher, a girl Holden likes. When Stradlater comes back from his date, he gets in a fight with Holden because Stradlater doesn't like the composition, which was about Holden's deceased brother, Allie's, baseball mitt, and Holden is worried that Stradlater tried to have sex with Jane.
Holden runs away to New York City and checks in at the Edmont Hotel. He is interested and aroused when he sees a couple in another room spitting at each other. Holden is bothered that he likes what he is seeing because he believes women should be treated with more respect.
Maurice, the elevator operator, offers to send Holden a prostitute named Sonny for 5 dollars and Holden agrees. When Sunny becomes aggressive with Holden, he becomes uncomfortable and tells Sonny he's injured so he can't have sex. Sunny asks for 10 dollars, but Holden only gives her 5 because that was the price Maurice quoted. Maurice beats Holden up and steals the other 5 dollars from Holden to give to Sunny. Holden feels horrible because Maurice lied to him.
Holden goes to the American Museum of Natural History to try to find his younger sister, Phoebe. Holden loves the museum because the displays and glass cases were the exact same as when he visited the museum as a little kid.