We last saw our heroes deep in the bowels of the Earth, outside a Granite fortress where the evil Metlar had just been set free by Tendril and D'Compose. Lasers fly and debris is tossed, and Metlar hypnotizes Dr. Bright, Herc, and Sandra Shore, freezing them until he can pick them up and toss them into his magma-boiling gullet. Just before they go down, Liquidator swoops by, macing Metlar with a chemical blast to the face, then Auger tosses a bomb beneath Metlar's foot, knocking the beast to the ground.
Earth Corps regroups and pins down the Inhumanoids while retreating into the Granite fortress. The Granites are missing, but Sandra's sensors reveal they're sheltered in a secret chamber. The Inhumanoids stop to banter about how big of an idiot Tendril is, and then they're attacked by the mysterious figure in the black environmental suit: Blackthorne Shore. He assaults Metlar with magnetic bolts, telling the thrashing and roaring Inhumanoid to bow to his will and help him rule the surface. Earth Corps doubles back and Sandra confronts her brother, but she's attacked by D'Compose while Tendril knocks Blackthorne aside. D'Compose uses his powers to infect Sandra, causing her to twist and grow and take on a monstrous, zombie-like form as she wails "I am one with D'Compose!"