Noted scientist Dr. Jordan Correll has discovered an amazing new mineral power source, but he had to crawl up out of the depths of the Earth to bring it back. Convicted murderer Marion Marshall Dix claims to have returned from the same Hell after being deposited there by an earthquake. Multinational conglomerate CalEx wants the discovery first … so a bad-ass team is organized to go get it, pronto.

Except the subsurface labyrinth known as the Underneath is not without its own civilization - not a Biblical Hell, but a practical one, which has just begun to send emissaries topside after years in shadow. One of these, a half-human, half-gargoyle named Kartkas, also acts as a guide for the exploratory sortie.

But this first contact isn’t so civilized. The Underneath teems with real monsters and double-crosses to challenge both our firepower, and the occult expertise of team lead Stephanie Billings, who has to tell the entire story of a first contact that actually dates back centuries - to our oldest fears, to our most classic nightmares of demons, devils and the battle to survive against them.