The saga of the Hanson family and friends continues as the group realizes that, although they survived a massive geophysical cataclysm unleashed in the northwestern part of the United States, they must now face something even more devastating. Having found refuge on St. Thomas in the U.S. Virgin Islands, they begin a new adventure: the fight to prevent human extinction from a horror of man's own creation. The tremendous forces of the cataclysm had caused the tragic and apocalyptic release of DM-19, a genetically engineered bio-weapon, from the "impenetrable" underground Black Diamond Military Base in Nevada. As the plague descends upon them at a frightening pace, a gut-wrenching sequence of events unfolds when they are caught in a race to unravel the mystery behind DM-19. It soon becomes apparent that this group forms the last-and only hope-for human survival. Their courage, intelligence, endurance, and love for each other will soon be tested beyond the boundaries of all human experience.