After winning a practice race, Speed Racer is offered a position on a team set to race in the Grand Prix. The company who employs his father, Pops Racer, a top engineer, owns the team. However, Speed declines because Pops doesn't want him to become a pro. Meanwhile, Pops quits when his plans to improve the Mach 5 are rejected.

While Pops and Speed are driving home, a gang of motorcycle racers steals their plans. Trixie, in her helicopter, runs the gang off the road and the plans are recovered. Back at the cyclist headquarters, bad guy Acey Ducey shows up and offers to get the plans for "5,000 clams." He confronts Pops but leaves empty-handed as Pops has hidden the designs on the Mach 5's windshield using invisible ink.

Deciding to sell the Mach 5 so Pops can rebuild the engine, Speed visits Sparky, who suggests that Speed enter the Sword Mountain Race for a $5,000 prize. While Speed takes the Mach 5 out for a road test, "dirty driver" Duggery rams the car, causing it to blow a tire.