It's the post-apocalypse, and the world has been changed by 'the accident,' a chemical warfare experiment gone awry. At an isolated subterranean complex, a group of people survives because they were able to get the antidote for the illness. They rescue a surface survivor from the gargoyles, who unfortunately had time to impregnate her, and when the 'baby' is born and escapes into the ventilation ducts, they begin experiencing an attrition problem.