Speed wants to turn professional, but Pops objects to his plans. Meanwhile, Pops plans to build a powerful new engine for the Mach 5 on his own after his employer rejects the design. But the executive is actually plotting to steal the design.

Continuing the race, Ace and his gang goes after Pops' designs. How will Speed Racer protect the designs from being stolen by the gang?

Speed is determined to enter his first big race against Pops' wishes. His drive to prove himself culminates in a challenge race on a stormy night against the Masked Racer (Racer X).

Speed is mistaken for the Masked Racer and taken prisoner by the Alpha Team. He escapes and drives in the big race, where he and the Masked Racer endure all of the team's dirty tricks.

Speed tries to figure out the connection between an escaped master criminal and the Model T car owned by a kindly, old man.

Captured by Tongue Blaggard, Speed devises a plan to get to the hidden billion dollars and get Blaggard arrested.