Donald wants to drive in midget auto races, and pesters the owners for a chance. He even wears crash helmet and goggles 24-7 in case of a driver calling and asking him to take his place. It finally happens when the driver of the 49 car gets a sore finger.
Huey gives Donald some bubblegum for the nerves. First event is to run in 12 seconds or less. He establishes a new world record, but in the hurry he drives the 3 car instead of the 49. When he runs in the 49, he's disqualified for driving the wrong way. Donald gets more nervous and Huey, Dewey, and Louie go in their pedal cars to give him more bubblegum, which embarasses him. Donald then makes the car trip and is disqualified again for crossing the finish line upside down.
The driver decides to fire Donald but keeps him to push the car. However, the 49 is disqualified again when it catches Donald's goggles and carries him on the track. The only work left for Donald is to add weight to the road flattener. As Donald is too light to help, he uses some boxes to weight more, but these had nails that fall and flatten most of the midgets' wheels. As the drivers angrily pursue Donald, they hurt their feet with the nails.
The only intact midget is the 49, and the only driver with sane feet is Donald. To have a race, Donald's nephews offer their help as competitors in their pedal cars. Donald eschews the bubblegum, but then runs on it and his car gets stuck, so the kids win the race.