When the railroad tracks through Sumner are abandoned, twelve-year-old Jess McCormick and his little brother, Brian, find an opportunity to capitalize on the situation. Seventy-five miles of railroad right-of-way become a go-kart highway, practically running through their backyard. With technical skills beyond those of their peers, endless resources, tools and used parts, they become entrepreneurs by opening up a custom go-kart shop in an old work shed behind their house. Their shop becomes the go-kart center of the trail. Every kid in Sumner and the surrounding area comes to see the small-engine whiz kids about getting modifications made to their go-karts. Everyone scrounges, saves and raids area junkyards in search of resources to build the faster, better go-kart. Some come by the local pizza parlor to challenge Jess, who is known all along the trail to have the fastest go-kart. The hard working boys make a few enemies along the way, but they also embrace friendships. They make a little money, hang out a lot, go on a few hairy rides, and even get a friend or two out of a tight scrape. It isn't until they venture into the world of Jr. Drag Racing that their mechanical as well as business skills are really put to the test.