The story begins with the discovery of a monstrous creature encased in an amber monolith buried in Big Sur national park, that is recovered by Earth Corps, a government-funded geological sciences research team.

Having pilfered the Earth Corps's engineering schematics via his ties to Masterson, Blackthorne joins the fray, now equipped with his own battle suit whose magnetic powers he wields against Metlar, only to be derailed by Tendril's interference while Sandra falls victim to the mutative touch of D'Compose.

Herc accompanies them to D'Compose's domain of Skellweb while Auger and Liquidator venture into Metlar's kingdom of Infernac and Bright convinces the Redwoods to help defend the surface world against attempts by the Inhumanoids to acquire sources of power.

Earth Corps is able to convince D'Compose to allow them access to Infernac—a deal made easier by the fact that the Inhumanoid already fears for his survival in the face of Metlar's insane plan—and they manage to defuse enough of the missiles to thwart the explosive scheme.

Visually, the show was distinctive for its application of heavy shadow, use of split screens, and occasionally brow-raising for its graphic content, such as monstrous amputations or writhing deaths by toxic waste, which promised to be hard-pressed to sneak their way into contemporary "children's hour" programming.

Having long-pursued a cryptic trail from native legend and archaeological artifacts, Blackthorne Shore arrives at a gruesome temple hidden in the wilds of Borneo, within which a snake-like Inhumanoid named Sslither has been imprisoned for thousands of years.

In a reckless PR stunt, Senator Masterson and tabloid-TV journalist Hector Remirez, together with a menagerie of inept celebrity goons, mount a live televised "journey to the center of the Earth" aboard a fleet of dirigible vehicles, promising to rescue the Statue of Liberty from Metlar's abduction.

Auger and company are content to let the inevitable televised chaos unfold, and instead busy themselves with the marriage of their teammate, Derek Bright, to actress Stella Blaze, a fiery redhead recently rescued from the adoring clutches of Tendril--who also decides to crash the wedding.

Derek and Stella Bright are enjoying their newlywed status as a celebrity couple even as the other members of Earth Corps increasingly find themselves basking in the media spotlight--except Auger, who seems to have been overlooked by fortune's calling.

The only character which was confirmed to reach the prototype stage by an ex-Hasbro employee was Sslither (the word "Slither" with a double S [although the animated designs of Tank, Sabre Jet, Nightcrawler, and Blackthorne's second suit all strongly indicate that they were adapted from intended toys]).

The 2020 miniseries Rom: Dire Wraiths by IDW Publishing set in the Hasbro Comic Book Universe features characters and references to Inhumanoids; for example, the Earth Corps are renamed as the Adventure-One Team.