Grace's friends are worried. Ever since she moved in with her new boyfriend, John, she's been behaving strangely. She looks pale, thin... ill. Is she on drugs? Fearing the worst, her friends decide to stage an intervention at the couple's isolated house. On arriving, they find the pale, sickly Grace being tended to by John, who turns out to be an authority on the occult. Grace, it seems, is not a drug addict after all. Her condition is the result of something horrible that was done to her during the brief time she was a member of an obscure cult headed by a mysterious man named Toth. The friends learn that John rescued Grace from the cult but that Toth is intent on getting her back and appears ready to mount an attack on the house that very night, using all the supernatural powers at his disposal. Even after they are warned by Toth to abandon Grace and John and flee the house before sundown, the friends, too wrapped up in their own trivial problems to see the dangers growing around them, dismiss the threat and continue to linger. That night, Toth summons to life the occupants of a nearby archaeological excavation, sending the undead army against the house and its unsuspecting occupants. As the assault on the house rages on and each friend in turn is killed, Grace reveals the reason for Toth's obsession with her.... While in the cult, she was forcibly impregnated by the demonic god the cult worships and she's now carrying its offspring.... Making matters worse, as Toth's minions claw at the doors, Grace's water breaks.... She can feel it coming... The monster child is about to be born!