Everyone on planet Zolpheid is killed in an Aquaphibian attack, except for Rald and Jerek. Receiving an SOS, Space City sends Fireball XL5 to rescue the two from Zolpheid's oceans.
Alan Fennell
Writer
John Kelly
Director
Gerry Anderson
Robert the Robot (voice) (uncredited)
David Graham
Lieutenant Ninety (voice)
Sylvia Anderson
Doctor Venus (voice)
Paul Maxwell
Colonel Steve Zodiac (voice)
John Bluthal
Commander Wilbur Zero (voice)
Guest Star