"Motocross was our life." For California-based brothers Trip (MIKE VOGEL) and K.C. (STEVE HOWEY) Carlyle, nothing matters so much as making good on their dead biker dad's dream to become champion Supercross racers. Trip rides like his father, a "free flyer," while K.C. is an old school rider who "plays it safe." This difference is figurative as well as literal, in the ways they approach their sport and their lives.
By day the brothers share duties in a pool cleaning business; this occasions K.C.'s meeting a rich-girl law student, Zoe (SOPHIE BUSH), with whom he develops a cursory relationship. Once he starts racing Supercross (many riders at once over an arranged course in an arena for screaming crowds), she cheers him on.
Highly competitive with each other, the brothers take different paths to their goal: K.C. plays by the rules (a more "old school" racer) and takes a "factory ride," a corporate sponsored position, racing as a "blocker" for the team's star, Rowdy (CHANNING TATUM). Both ride for Team Nami, a company owned by Rowdy's father, Clay (ROBERT CARRADINE).
On the other side of the film's simplistic divide is Trip, riding as a "privateer," under the auspices of Hogs' Heaven, a small, un-corporate outfit owned by Earl (ROBERT PATRICK). Trip also develops a romance with Earl's daughter Piper (CAMERON RICHARDSON), and exchanges glances with her brother Owen (AARON CARTER), initially identified as Hogs' Heaven's best rider. He hen essentially disappeared from the film once Trip begins racing for the team.
As the brothers compete, they argue occasionally (at their shared apartment), and eventually realize they both want to win races and also do it without corporate sponsorship, to stay true to their dad's dream. They work together -- playing it safe but also free flying -- to make this happen.