Brothers Aaron and Ashton Mason have very active imaginations. In particular, they’re fond of racecars and the Indy 500. In the safety of their basement, they pretend a cardboard box is a fast-moving car and even manage to win a race or two. In their minds, they can hear the roar of the engines and cheers from the crowd.

Of course, racing cars can be dangerous, so their playtime is sometimes interrupted by crazy crashes and emergency visits to the pit crew. They soon find a second cardboard box. Now, Aaron and Ashton can race against each other. But this time something feels different. The cheers are a little bit louder, and suddenly, things change.

No longer in their basement, the brothers find themselves roaring through the real Indy 500! They have no idea how they got there, but they better figure it out or they could be in big trouble. After all, Mom hates when they miss dinner. To make it home, the boys must work together as they embark on the adventure of a lifetime at the racetrack.