Five ships disappear in the Sargasso Sea. Finally, there's a survivor, who describes a ""thin, red light"". The authorities bring in noted scientist Dr. Benton Quest. Together with son Jonny, bodyguard Race Bannon, and (of course) Bandit the dog, Dr. Quest investigates. Someone is conducting laser experiments from a converted galleon, and plans to shoot down the new Man In The Moon rocket! It's up to Jonny, his father, and their friends to stop this scheme.