The Tigers' Branch Turner wants to steal more bases than any other player in the Union City Pony League. Then Coach Tillman from the Currants, the Tigers' biggest rival, tells Branch about "bam." This begins Branch's search to discover the most important part of baseball. Branch's journey will include his old-fashioned teammate Pine Tar Yore, the Currants' show-off Eli Tillman, the dangerous fastball pitcher Louie Horton, and many other colorful players. So what is the most important part of baseball? Is it winning? Having fun? Playing by the rules? Or is it something else?