The Catcher in the Rye covers three and a half days in the life of sixteen-year-old Holden Caulfield.  Holden narrates the story, looking back some months later from the vantage point of a temporary, enforced stay in a psychiatric institution in California, where he's visited by his older brother DB, a Hollywood writer.  His younger brother Allie died three years previously from leukaemia.  He also has a younger sister, Phoebe, who lives at home with their parents in New York City.

When the story begins, Holden has been kicked out of Pencey Prep, a private boy's school in central Pennsylvania ("about the fourth school" he's gone to), for flunking four out of five subjects.  Deciding to leave on the Saturday night before Christmas break, Holden heads for home in New York City.  He can't go to the family apartment, however, because they don't yet know he's flunked out of Pencey and aren't expecting him until the official school break on Wednesday.  Holden has a few days to kill.

Loaded up with cash (from his grandmother, who sends him birthday money "about four times a year," and from selling his typewriter to a schoolmate), Holden takes the bus to New York and checks into a motel.  In the adrenalin and alcohol-fueled days that follow, Holden can't stop thinking, and can't stop moving.  

Because of his height (6ft 2½), his partially graying hair, and his sophisticated vocabulary, Holden at sixteen folds in and out of adult society, sometimes pulling it off and sometimes not, while privately occupied by thoughts of where the ducks in Central Park go in winter, and how incredibly phony a large percentage of human interactions are. 

He heads from the hotel bar (gallantly buying drinks for older women, but reduced to Coke himself when the bartender refuses to serve him alcohol) to a trendy jazz club, then back to the hotel where he's beaten up by the elevator man/pimp after a transaction gone awry.  So ends day one.

Day two, Holden continues an increasingly hyperactive search for company and entertainment.  Leaving the hotel, he checks his bag at Grand Central Station before meeting Sally, a sort of girlfriend, for a show and ice skating.  Insulting her in a scotch-fueled moment of truth telling, he amuses himself with the Christmas show at Radio City (which he despises), meets a guy he doesn't like at a bar, and stays on to get drunk. Finally, after roaming Central Park to see for himself where the ducks go in winter, he decides to visit Phoebe, and sneaks into the family apartment.

Ten-year-old Phoebe understands immediately that he's been kicked out of Pencey, and calls him on it.  While he's trying to convince her that he's ok, his parents return and Holden is on the move again, this time phoning a former teacher, Mr. Antolini, who invites him over though the hour is late.  It seems Holden will get some sleep at last, but he flees Mr. Antolini's apartment as well after his teacher appears to make a pass at him.

After crashing on a bench at Grand Central Station, Holden comes up with a plan to head west and live out his life as a gas station attendant.  Before starting out, he wants to say goodbye to Phoebe, and he leaves a note at her school asking her to meet him at the Natural History Museum.  What he doesn't anticipate is her wanting to go with him, lugging her suitcase across Fifth Avenue.  The two fight, and he checks the suitcase at the museum.  Walking through Central Park with Phoebe, visiting the zoo and the carousel, Holden realizes he can't run away from his life or his family.  He promises Phoebe he will go home.