Speed Racer is a young excellent driver. He wishes to join a professional team but knows that Pops wouldn't allow it.
Pops tries to show his plans for a new, faster engine to the board of the company he works at. An exec, Mr. Van Ruffle, says the plans will fail. Outraged, Pops quits to build the engine on his own.
As Speed drives Pops home, a gang of motorcycle riders try stealing the plans. A struggle ensues and they manage to get the plans back. Since there was an attempt, Pops knows they must be worth something.
Van Ruffle is outraged that his men couldn't steal the plans. Thug, Ace Ducey offers to steal the plans for him if he'll pay him $5,000 dollars.
Speed plans to sell the Mach 5 in order to get some money so Pops can build his new engine. Sparky suggest he enters the Sword Mountain Race in order to win the cash prize. Since it'll be a tough race, Sparky suggest adding something that will help him climb mountains.
Ace Ducey confronts Pops in his shop in order to steal the plans. Speed arrives so Ace leaves. Speed goes after him and Pops marvels over his decision to write the plans in invisible ink on a car windshield.
After Sparky modifies the Mach 5, Speed takes it for a test drive. Speed's rival, Duggery comes and causes Speed to crash the Mach 5. Speed and Sparky repair the Mach 5 but are missing a windshield. Speed says it's too late to look for one and will race without one. Sparky warns him it'd be too dangerous. Then Spritle and Chim Chim arrive with one they found, the one with Pops' plans (although no one knows that). Spritle tells Pops that Speed will be using the windshield and accidentally tells him Speed will be racing. Pops decides he needs to get the windshield and Ace Deucy overhears him saying the plans are on there. When Pops tries to stop him, Ace knocks him out.
As the race begins, Deucey and his men target the Mach 5, eliminating other cars that get in their way.