Ten years after escaping from Cretacea, Jordan and Jason are forced to return there as the hostages of a militant group of Native Americans. There, they discover that the United States government has turned the subterranean prehistoric world into its own private laboratory. When Jason and one of the Sioux braves become infected with Organism Alpha, the group must reveal its presence in hopes that the researchers have a cure for this lethal disease. Fortunately, they are correct. Inside the huge complex which has been constructed next to Lava Lake, they begin to learn the scope of the military's agenda. They are only told part of the whole story though, the part that's ingenious and acceptable. The engineers have concluded that Jason's father, Nathan, was correct and Cretacea is unstable. They are involved in an effort to rescue the many endangered species which live there. There is, however, one species for which there is no place on the face of the Earth from which mankind would be safe; the Chill, the giant arachnid predecessors to the subphylum Chelicerata. Their plan is to transplant them to Europa, a moon of the planet Jupiter. It has previously been determined that a liquid sea exists beneath its frozen surface. The scientists intend to create an ecosystem like the one in Cretacea around the hydrothermal vents which have been discovered at the bottom of the alien ocean. In order to be sure that the Chill can survive in this extremely hostile environment, they have experimented with the Chill using gene-splicing. They've taken the most dangerous predator ever to exist on Earth and attempted to improve it. Unfortunately, by using genetic material from a highly classified source, they've more than succeeded.