The first really significant event is Finny's breaking the school swimming record and demanding to keep it a secret between Gene and himself. Then Gene, in an act of blind malice born of his own sense of inferiority to Finny, deliberately jounced the tree limb causing Finny to fall and break his leg. After this incident, other significant events follow in succession.
Gene goes to Boston to confess, but Finny won't let him, leaving Gene to deal with his guilt. Gene attacks Quackenbush, a result of his own guilt. Gene plans to enlist, but gives it up when Finny returns to school. Brinker confronts Gene in the Butt Room, hinting at the truth of Gene's betrayal of Finny. Leper returns to Devon after going AWOL from the Army. Gene visits Leper in Vermont and faces the reality of what the war has done to Leper. Gene and Finny both submit to the Trial that Brinker organizes in the Assembly Building, during which the truth emerges. Finny runs from the Trial, falls down the marble stairs, and breaks his leg again. Gene visits Finny in the infirmary, and they openly discuss for the first time what happened in the tree. Finny dies. Gene attends his burial but finds he cannot cry. Gene experiences the argument between Brinker and his father which gives him insight into the true cause of war. Gene leaves Devon after graduation. Gene returns to Devon fifteen years later, seeking understanding of the events that had occurred there and some final peace.