Charlie, who is nervous about his first day of school, and Dumpy the Dumptruck, who is nervous about his first construction job, gradually adjust to their new settings after making new friends.
After Charlie and his grandfather fix up a rusty old dump truck, they use Dumpy to help Trundle the tractor, Bee Bee the backhoe, and Stinky the garbage truck build a new barn.
Curious George gets into trouble when he boards a dump truck and spills a load of dirt in a pond but redeems himself when the dirt creates an island for the pond's ducks.