"Big Bub the monster needs to take a taxi, but the car is too small. What will he do? It's time to get creative"--

For Enzo, the Fourth of July means three things: fireworks, family, and car races! This year Zoë is finally old enough to compete in the Kids' Kart Challenge. But when one of the boys at the track says that girls aren't fast drivers, Zoë gets nervous and backs out of the race. Enzo knows it's up to him to help his family regain the confidence to compete on the big day.

Gus's workshop is chockful of useless odds and ends. But when his friend Rico comes over with a problem his scooter seat is way too small for a rhino Gus finds just the thing to solve it. He creates a fabulous new vehicular contraption with an old lounge chair! One by one Gus's friends bring him their vehicles and Gus solves their troubles with ingenious solutions a cooling system made with a fridge that doubles as ice-cream machine, a burst of speed...