Gene, who is a inverted and smart young man, is friends with Finny, his total opposite. Finny is good at sports and is very outgoing and spontaneous. They both attend the Devon school during the year 1942 and go on risky adventures during the summer that could get them into lots of trouble, if it weren’t for Finny’s talent of talking himself out of things. During the summer, the two boys form a club called the Super Suicide Society of the Summer Session, at every club meeting it was tradition that the two boys jump off of a tree limb together. As the days go by Gene begins to feel insecure about his importance in the friendship and also becomes very envious of Finny and his skills. Gene reasons that Finny is actually distracting him from his studies because he is jealous of his smarts. At the next club meeting, Gene subconsciously jounces the limb and lets Finny fall hard. The result are two broken legs for Finny and the whole tragic fall is considered an accident and no one thinks to blame Gene. However the amount of guilt Gene feels adds up even more when he learns that Finny can’t participate in the one thing that he loved most, sports.

Although Gene tries to confess to Finny that he was the cause of his broken legs, Finny refuses to listen to him and even threatens him to shut up. Gene drops the subject altogether and continues on with his schooling at Devon. The summer session has ended and world war 2 is now the main priority to Gene. He tries not to focus on sports by becoming a manager of a team and then makes it a plan to enlist in the war with Brinker. However, that same night he made that plan was the same night Finny returned back to school. When Finny finds out that Gene is going to enlist in the war rather than play sports, he makes a point that the war is all a big joke made up by fat old men. Of course, Gene buys into his theory and continues to follow Finny’s orders. Gene even trains for the Olympics in place of Finny just to satisfy his dreams.

During a winter carnival, that was set up by Finny, Gene receives a note from Leper, a sweet and nature-loving boy who went into the war with high hopes, is now crying out for rescue. Gene goes to Vermont and finds Leper has a crazed mindset. That is when Gene becomes scared of the war and runs back to Devon to confide in Finny about it. Later on, Brinker becomes suspicious that Gene had something to do with Finny’s accident so he arranges a tribunal with his peers and snatches Gene and Finny into the auditorium. There the boys throw around questions at Finny to see all of what he remembers about that tragic day, and when that isn’t working out, the boys summon Leper to the auditorium to justify what happened. Leper knows that he has important information so he tells them everything, besides the fact whether Gene pushed Finny off the tree limb or not. Suddenly, Finny remembers everything and becomes furious with the fact that his best friend would be involved in such a cruel action, so he storms the auditorium and heads for the stairs. Rushing onto the stairs in the dark, Finny falls and breaks his legs again.

Not knowing what to do that night and only acting on his emotions, Gene visits Finny at the hospital who then rejects him from being there and being his friend. Gene leaves that night and sleeps under the school football stadium until the next morning when he goes back to the hospital. The two make peace with each other after explanations and apologies. However, later on, Gene finds out that Finny has died from some bone marrow that has entered his bloodstream and went into his heart killing him instantly. Gene takes the news rather well and doesn’t cry for Finny when he attends his funeral. Gene feels like he died with Finny because he was always a part of him. In the finale chapter, the boys are seen graduating and off enlisting into the war. However, Gene claims that he has already fought his war in Devon and has never killed anyone beyond that point. Gene reflects that everybody he knows consist of hatred and ignorance that drives them to be violent. gene believed that this was something Finny never obtained which made him different from anyone else he has ever come in contact with.