Girl Daredevil (Part 1)

At the base of a tall building, Speed and company watch Twinkle Banks, star of the Universal Circus, dive off the top. Then, at the circus, they watch Twinkle drive a race car and perform daredevil stunts. She worries about maintaining the car's momentum and faints. Speed rescues Twinkle. While the girl daredevil rests in bed, a clown (her father) tells Speed that because of a money shortage, he's having difficulty keeping the track in good repair. Speed makes a donation. Later, Speed and Trixie learn on the radio that Twinkle will drive a car, balanced on two ropes, over Niagara Falls. Because of the strong winds Speed and Trixie try to stop Twinkle.

Meanwhile, Cornpone Brush, who financed the stunt, tells the clown that Twinkle will perform regardless of the hazardous weather. When Speed and Trixie arrive, Twinkle is already making her way across the Falls. Away from the crowd, Brush reads an old map. It identifies a secret cave in back of the Falls that leads to treasure. His thugs lower a gigantic pipeline into the Falls and Brush drives into it to discover the cave's entrance.

Back at the stunt show, the wind causes Twinkle's car to plunge into the Falls, leaving her hanging onto one of the ropes. Speed drives the Mach 5 on two wheels down the remaining rope to rescuer Twinkle. He grabs her. The rope snaps and they plunge into the Falls. Attempting to drive along the bottom, Speed gets caught in a series of whirlpools. With little oxygen left in the cockpit, Speed and Twinkle pass out.

Cast

 * Peter Fernandez: Speed Racer, Racer X
 * Corinne Orr: Trixie, Spritle Racer, Mom Racer
 * Jack Grimes: Sparky, Chim Chim
 * Jack Curtis: Pops Racer, Inspector Detector