Chapter 1: The narrator (Gene) returns to the Devon School in New Hampshire, that he graduated from 15 years earlier. He goes to a certain tree and switches back to the past. Phineas dares everyone to jump from a branch in the tree into the river. Phineas, and Gene both jump. On the way back Phineas and Gene play fight so that they are late for dinner.
Chapter 2:Mr. Prud'homme, a master, stops by the boys' room to scold them for missing dinner again for the ninth time in two weeks. Phineas explains that they were late because they were jumping out of the tree to toughen up for the war.
Mr Prud'homme, accepts the explanation because, he, and everyone else, feel sorry for the boys that will soon have to go to war.
Chapter 3: The boys join The Super Suicide Society of the Summer Session. The club meets every night. Phineas and Gene open each night by jumping out of the tree. They make a new kind of war game called blitzball, in which everyone is everyone elses enemy. Phineas breaks the schools swimming record, but tells Gene not to tell anyone, he just wanted to do it for himself. Gene and Phineas of campus to the ocean to swim. They have a drink at the bar, the spend the night on the beach, and Phineas tells Gene he is his best pal. Gene is not sure if he feels the same.
Chapter 4: Gene and Finny (Phineas) wake up and head back to Devon. Gene fails his trigonometry examination for the first time. Finny tells Gene that he studies too much. Gene thinks Finny is jealous. Gene wants to earn the
Scholastic Achievement Citation to get even with Finny. Gene knows that Finny must be best and that he cannot be best if Gene becomes even with him through his studies. Gene decides that he and Finny are locked in a complete enmity rather than friendship. Finny announces Leper's intention to jump from the tree and coazes Gene away from his studies. Gene and Finny are going to jump together,
Finny falls to the ground, then Gene jumps into the river.
Chapter 5: Finny has a shattered leg. Gene bears private guilt. He puts on
Finny's clothes and the sensation excites him. Dr. Stanpole, the school physician, informs Gene that Finny wants to see him. Finny recalls the fall, and expresses that he thought Gene wanted him to fall. Gene is about to confess when
Dr. Stanpole interupts. Finny is taken to his home near Boston and Gene returns