Because they are far underground inside the Dona Inez Caverns when the cataclysmic event occurs, a small group of ecotourists miraculously survive. But civilization, they soon discover, now lies in ruins; the world as they have always known it has been irreparably destroyed. Yet not all living things have succumbed to the cataclysm, and various tattered fragments of life, human and animal, still persist. This small group of ecotourists quickly learn that their continued survival will depend entirely upon their courage, ingenuity, and perseverance. And they also quickly learn that for them and for the various others in the world who have also managed to survive, once civilzation is gone, so are most of the humanistic and moral values that serve to hold man's heart of darkness in check.