A U.S. space probe discovers a 65 million-year-old derelict outpost at the moon's south pole. Now the owners of the moonbase are returning to reclaim their home world--our world. In Montana, wildlife biologist Chase Armstrong and rancher's daughter Kit Daniels survive attacks by T-Rex and deadly Megaraptors to find that they are at ground-zero, where the invaders' lost city lies buried under a mountain of sandstone. Deep in the underground catacombs, trapped by human-sized, intelligent carnivorous dinosaurs, they may be mankind's last hope for survival."Solid science and pacing that never quits." --Kay Kenyon, Philip K. Dick Award nominated author of Maximum Ice"Fills the void since Jurassic Park. And, Hopp's book may be better." --Steve Brusatte, DinoLand Review