"A Separate Peace" by John Knowles is primarily about two boys, Gene and Finny, who are both enrolled at the Devon School in New Hampshire. Finny is a prankster and quite athletic, while Gene is more straight-laced and academically inclined. Gene becomes jealous of Finny's abilities and secretly believes that Finny is trying to sabotage Gene's academic career.
The two start a ritual of jumping out of a tree on campus and into the river below, which, in turn, begets a secret society. When Gene learns that Finny only has Gene's best interest at heart, shocked at this realization, Gene inadvertently bounces the tree limb slightly when Finny is about to jump. Finny falls and breaks his leg, which ends his athletic career. Gene tries to apologize on numerous occasions, but Finny wants to hear nothing of it.
Another friend, Brinker, wants to prove that Gene bounced the tree limb on purpose. He invites Leper, a World War II runaway who has gone slightly mental, to come speak during a secret gathering of the society. Both Gene and Finny act as though they do not know the truth. Finny leaves and falls down the stairs, breaking his leg again. Finny finally accepts Gene's apology for having a major part in having broken Finny's leg to begin with.
During the surgery to correct this broken leg, marrow gets into Finny's bloodstream, killing him. While the other boys go off to war, Gene stays behind, reflecting on the hostility of the human heart. He believes that only Finny was not vulnerable to that feeling.