In 1983, Richard Papen transfers from a college in his hometown of Plano, California, to Hampden College in Vermont, taken in by the beautiful scenery in a brochure. After experiencing some pushback, Richard is accepted into an exclusive ancient Greek program taught by Professor Julian Morrow, with five other students, Henry, Bunny, Francis, and twins Charles and Camilla. The other students are extremely wealthy, and Richard attempts to hide the truth of his economic background from them. Richard feels like an outsider at first, especially as he was forced to drop all his other classes to study with Julian. However, once Richard is invited to spend weekends with them at Francis’s country house, he begins to feel more a part of the group. 

Over winter break, Richard remains at Hampden, continuing to work for a psychology professor to earn money while living for free in an unheated warehouse. Richard suffers from cold and exhaustion until he is found by Henry, who has returned early from his trip to Italy with Bunny, and takes Richard to the hospital. Henry then allows Richard to stay with him until the dorms reopen. After Richard moves back to his dorm, he returns to Henry’s apartment for a textbook. There, he finds that Henry has booked four tickets from Boston to Argentina for himself, Francis, and the twins. After Richard realizes the four of them did not leave, Henry confides in Richard that they had planned to escape the country but could not get enough money to do so. Henry tells Richard of how they had a bacchanal at Francis’s country house, trying to achieve a state of Dionysiac madness, which they had discussed in Julian’s class. In the woods, they killed a farmer and left his body behind. 

Though none of them told Bunny about the farmer, he read about the man’s death in the paper and began to make jokes about the four of them committing murder. While Bunny and Henry were in Italy, Bunny read Henry’s journal, in which he wrote about the farmer. Henry and Francis have been paying for everything for Bunny to keep him quiet, though Bunny is getting more demanding and is taking his anger out on all of them. Henry toys with the idea of poisoning Bunny but eventually decides they will push him over a ravine while he is on his weekly hike. Richard is not supposed to join them, although on the day of the planned attack, Richard finds a note from Bunny in the library stating he has gone to a party. Richard goes to the woods to tell the others that Bunny will not be coming. However, Bunny does arrive, confused to find his friends there before they push him over the edge.

Snow begins to fall soon after Bunny is dead, so his body is not found for several days. During that time, the FBI descends on the campus, believing Bunny’s disappearance is related to drug dealing. After the snow melts, Bunny’s body is found, and his classmates go to his family’s home in Connecticut for the funeral. When they return to campus, they do not spend as much time together as they did before. Charles begins drinking even more than usual, getting pulled over while driving drunk, and passing out on a playground. Francis believes he is having a heart attack, which turns out to be anxiety. Richard begins to realize things about his friends, such as the fact that Charles and Camilla have a sexual relationship, and that Camilla and Henry have been manipulating him all along.

Richard and Francis take Charles to the country house, as Charles is increasingly paranoid about what Henry will do to him. Charles disappears after Henry calls, and Richard and Francis go to the hotel where Camilla has been staying to look for Charles. There, they find Camilla and Henry, who have begun a romantic relationship. Charles arrives with a gun, which Henry gets a hold of in the ensuing confusion. Henry whispers something to Camilla and then shoots himself in the head. After Henry’s death, Francis, Charles, and Camilla all leave Hampden, and Richard is the only one to graduate. The four of them grow apart, though Richard visits Francis and Camilla after Francis attempts suicide, and he learns that Charles and Camilla no longer speak. Despite the years that have passed, Richard remains in love with Camilla and still dreams of Henry.