Ep. 23: Speed confronts Cumulus at his underwater base, leading to a fatal confrontation involving Dr. Nightcall's daughter.
Aired on September 3, 1967
Speed pursues Cumulus to his undersea base, where he discovers the villain's plan to destroy all global military installations. During the ensuing conflict, Dr. Nightcall's daughter attempts to intervene but is killed. Speed ultimately defeats Cumulus by throwing him from a duplicate Mach 5. In the aftermath, Dr. Nightcall vows to dedicate his life and the base to undersea research as a tribute to his deceased daughter. The episode concludes with this solemn commitment to scientific advancement in memory of the loss suffered during the confrontation.
Episodes
- Ep. 19 · Speed and Twinkle confront Cornpone Brotch at his Mount Rushmore hideout.
- Ep. 20 · Oriena Flux seeks the GRX engine while Pops confronts her about its dangerous past.
- Ep. 21 · Pops rescues Speed from Oriena's gas-enhanced test drive and helps him overcome his fear of speed.
- Ep. 22 · Dr. Nightcall and daughter steal the Mizmo Beam to build a flying Mach 5 with an atom bomb for Cumulus.
- Ep. 23 · Speed confronts Cumulus at his underwater base, leading to a fatal confrontation involving Dr. Nightcall's daughter.
- Ep. 24 · Prince Jam and Spritle collide during a youth race after a kidnapping plot
- Ep. 25 · Spritle and Prince Jam stop plotters and the prince is crowned
- Ep. 26 · Janine Trotter faces her father's sabotage of a speedway and car brakes while Speed and Sparky intervene.
- Ep. 27 · Speed confronts gambler Mr. Fastbucks after he hijacks the Mach 5 during the Monte Carlo Rally