Will Christopher ever learn to behave? His parents, teacher, and principal have tried to explain the difference between appropriate and inappropriate behavior in school, but Christopher loves being the 2nd-grade class clown. He can't resist making fart noises, sliding down the banister, or falling out of his chair for laughs. When his dinosaur friends Tommy T-Rex, Tiana Triceratops, and Terry Pterodactyl take their goofing off too far, one of them ends up in the hospital. Thanks to their antics, Christopher learns how his reckless classroom behavior can endanger himself and others.