THE HERCULOIDS...

The Herculoids battled to defend their planet from menaces on Amzot/Quasar and from outer space. All of the Herculoids displayed Human-level intelligence as well as emotions, and Zandor and Tarra both displayed a working knowledge of complex alien technologies as well as the ability to pilot interstellar spacecraft—but essentially, Zandor, Tarra, Dorno, and the Herculoids were fighting to keep Amzot/Quasar a technology-free, primitive planet. This is further indicated by the pseudo-barbarian outfits of Zandar, Tarra, and Dorno and the fact that technology was used mainly by the various villains, but rarely if ever by the heroes. Although the "speech" of their companions was limited and repetitive, Zandor, Tarra and Dorno demonstrated that Gloop and Gleep, at least, had a comprehensive mode of communication, and that they could at least understand and interpret this language (c.f. "The Mutoids:" "Gleep says that the aliens who landed are attacking Dorno and Tundro"). The "voices" used in the shows were actually brief tracks supplied by two actors and reused throughout the series, in keeping with Hanna-Barbera's thrifty ethos.

A number of episodes featured alien invaders who came to Amzot/Quasar to seek revenge against Zandor for an unspecified battle or adventure from the past. All were apparently technocratic and the alien's grudges seemed to basically boil down to them being stymied in their attempts at bringing technology to Amzot/Quasar, which the apparently primitivistic Zandor wanted to avoid.

The show's opening theme was a fully orchestral composition, suggesting uncommon heroism. An alternate opening theme was also utilized for some episodes. All of the show's incidental music was recycled from Jonny Quest.[citation needed]

In some of the seasons, the episodes opened with the following narration: "Somewhere out in space live The Herculoids...Zok the laser-ray dragon! Igoo the giant rock ape! Tundro the tremendous! Gloop and Gleep, the formless fearless wonders! With Zandor their leader, and his wife, Tarra, and son, Dorno, they team up to protect their planet from sinister invaders! All-strong! All-brave! All-heroes!! They are The Herculoids!!!"