Jerry Spinelli's "Crash" novel takes place over the course of John "Crash" Coogan's seventh grade year with brief glimpses of his life when he was younger. During his seventh grade year, John is forced to confront his changing stances on violence, aggression, and bullying. In particular, John has to think about who he really is and whether his true thoughts, feelings, and actions match up with the ultra-competitive and physically dominant jock "Crash Man" persona that was given to him when he was just a little boy. John's changing relationships with his neighbor and bullying victim Penn Webb, best friend and fellow football player Mike Deluca, and beloved grandfather Scooter help shape John's transformation from someone who always did what others expected of him to someone who acts with more sincerity and stays true to his thoughts, opinions, and beliefs.

At the beginning of the novel readers meet the one person who does not call John "Crash," Penn Webb. Penn moves to John's Pennsylvania neighborhood on the eve of the boys' first grade year. Penn, a true nonconformist, represents so many things that go against what John believes in: violence, wealth, and athletic ability. Most important, however, is Penn's stance of non-confrontation. John tries repeatedly to tease, provoke, and harm Penn, but Penn does not engage in a confrontation with John. This sticks out to John because he is used to scaring people off or else being challenged by them. The years pass and John avoids Penn, who remains friendly to him. In sixth grade John meets Mike Deluca, the first person to equal John in terms of loving conflict, football, and fighting. They become good friends, and Mike often ropes John into his stunts to bully Penn. John agrees to participate in them.

Now in seventh grade, the boys are thrilled by the appearance of new girl Jane Forbes, but John's efforts to talk to her are squashed when she all but ignores him. John's parents are absent much of the time because they have grueling jobs. John's little sister Abby is friends with Penn and adopts some of his causes, such as conservationism, sustainability, and being eco-friendly. In the first football game of the season John scores a record-breaking number of touchdowns in a single game, but he is frustrated that neither of his parents showed up to watch him, especially because Penn's parents are there to support Penn's cheerleading efforts. But when John comes home he is delighted to find his grandfather, Scooter, cooking in the kitchen. John can hardly believe that his beloved Scooter is back, but it seems he will be moving in permanently. John's mother (Scooter's daughter) reveals that she will be getting some new real estate business with the construction of a new mall. John and Abby enjoy Scooter's nightly storytelling efforts, which send them into shrieks of terror, and also trust Scooter as a confidant. Scooter also supports his grandchildren by supporting Abby's backyard habitat project and attending John's practices and games.

At a school dance John attempts to flirt with Jane and get her to dance with him, but she rejects him and calls him out for being an inconsiderate bully. John is enraged when Penn shows up because it angers him that Penn is able to break through Jane's icy attitude and befriend her. Meanwhile, Abby protests the mall on TV, which frustrates Mrs. Coogan. At Thanksgiving, John tackles Scooter and worries that his grandfather is getting old. In December Scooter is hospitalized after having a massive stroke. While he is in the rehab center the Webbs reach out to the Coogans with food, and Penn even gives Scooter his Missouri River Mud which has supposedly magical medicinal powers. Over Christmas break Mike and John get into a fight when Mike finds and wears Scooter's hat. This signals the beginning of the end of their friendship, which erodes further in the new year at school when Mike ramps up his bullying game and targets Penn. John wants nothing to do with this and intervenes. Penn has started to run around the neighborhood at night, and eventually John discovers that Penn is hoping his great-grandfather can see him race in the Penn Relays when he visits this spring. John joins the track team as well. Scooter improves enough to come home, but all he can say is "A-bye." He also has physical limitations.

In the climactic scene of the novel, John and Penn compete in a race-off for the remaining spot on the school's Penn Relays team. John lets Penn win on purpose. John shows more compassion in general now and helps Abby with her wildlife habitat project. Mrs. Coogan announces she will be working only part-time from now on, and John encourages her to resume her painting hobby by buying her paints. At the end of the novel, Mr. Coogan has made peace with the wild backyard, John is going to a party at Jane Forbes' house, and Penn is his best friend.