Speed Racer (Emile Hirsch) is an 18-year-old whose life and love has always been racing. Racing is "in his blood": his parents, Pops (John Goodman) and Mom (Susan Sarandon), run an independent business building racecars, and his brother, record-setting racer Rex Racer (Scott Porter), was killed in Speed's childhood in the running of the Casa Cristo, an incredibly intense cross-country racing rally notorious for rough and foul play. Before his death, Rex was rejected by his father for his choice to run the Casa Cristo, and publicly defamed for appearing to cheat underhandedly in a race. Now, Speed Racer is quickly sweeping the racing world with his artistic skill, driving the "Mach 5" of his fathers design, but remains interested only in the art of the race and the well-being of his family. When Mr. Royalton (Roger Allam), owner of conglomerate Royalton Industries, offers Speed an astoundingly luxurious lifestyle in exchange for signing to race with him, Speed is tempted but declines, knowing that his father would never wish Speed to sign with the very power-hungry corporations he so mistrusts. When Speed refuses Mr. Royaltons offer, Royalton reveals that top corporate interests, including Royalton, are fixing races and cheating to gain profit, and then threatens Speeds career success and very life when he still does not agree to sign on. When Royalton later proves ready to make good on his threats, Speed teams up with his girlfriend Trixie (Christina Ricci), his one-time rival, Racer X (Matthew Fox), and shifty Japanese racer Taejo Togokhan (Rain) to enter the Casa Cristo known as "The Crucible" in part of a plot to uncover the treacheries of Royalton and save the Racer business. Despite his fathers initial anger at his racing in the Crucible, his family eventually joins up as well, as Speed overcomes Royaltons brutal team and many seemingly-unsurpassable obstacles to win the Casa Cristo, and, finally, the Grand Prix, returning racing to its true purpose and exposing Royaltons corruption. Furthermore, it is revealed to the audience at the movies end that Rex did not really die (and also did not cheat), but instead underwent plastic surgery to reemerge as Racer X, helping his younger brother finally save his family and his sport.