From the instant he arrives at his grandfather's house in Oelwein, Iowa, David fears the drought-stricken summer signals a bad omen for his yearly visit. His parents, who are back in Chicago, are experiencing serious marital problems, for which David feels partly responsible. Miss Holcomb, Grandpa's neighbor, always competes against David and his grandfather at the county fair. She always wins the blue ribbon for the best tomatoes. David and his friend, Katie, find out that Miss Holcomb has been spreading lies about Grandfather. They set up a plan to retaliate. Armed with their knowledge and a gunnysack of red balloons, they plan and execute an attack, aimed at teaching Miss Holcomb a lesson. Young friends of David's help him create a newspaper called Kids' Register. The story continues as a large group of children go to the Fayette County Fair where the winner of the tomato contest is divulged. The end is a bittersweet moment when David and the archenemy, Miss Holcomb, discuss why marriages fail.