Dr. Quest receives a call from the governor of Bahiti. The governor is concerned about Mount Tahawa, a volcano which is displaying some unusual and disturbing properties. As the governor is explaining this, a man named Simon-11 listens...
A deadly tarantula and a hanger fire are meant to discourage investigation, but Dr. Quest and Race overfly the volcano anyway -- only to be knocked out of the sky! They eject, but are captured by Simon-1, chief enforcer for ... Dr. Zin!
Dr. Zin has developed ""the greatest destructive force the world has ever known"", and plans to make it available to the highest bidder. Captured, Dr. Quest and Race can do nothing. But Jonny and Hadji are still free... A police sergeant drives them to the mountain, but Simon-3 spots the car. The sergeant is waylaid, but the boys elude capture, and enter the base. Inside, they use trickery and bad driving to free Dr. Quest and Race. Together again, the team escapes the base.
They're not out of danger yet. Flyin