What happens in change up by John Feinstein?

In "Change Up" by John Feinstein, a group of young Baseball players and their coaches face various challenges during a summer baseball camp. The story focuses on the relationships between the players, their passion for the game, and the lessons they learn about teamwork, sportsmanship, and personal growth. As they navigate competitive pressures and personal conflicts, they also discover the importance of friendship and resilience in the face of adversity. The narrative blends humor with the realities of youth sports, ultimately highlighting the joy of playing baseball.