A massive dust-storm cutting off communications and obscuring visibility. A father, his estranged son, and a small band of survivors marooned, waiting for help, unaware of the things that are out in the dust, waiting, watching, drawn by the scent of blood.

    A team of fossil-hunters... A desperate fight to survive... Park Ranger Hannah Kates is leading a group of gifted teens on a fossil-hunting field trip when a rock slide uncovers a portal through time. They are whisked back to an era when giant predator mammals roamed the earth. They want, desperately, to find their way home. But first, they have to survive a world where bizarre--and hungry--mammals ruled North America. They have to survive the Dawn of Mammals. In Book 1 of the series, Hannah and nine teens are thrown back thirty million years to the world of saber-toothed nimravids, ferocious carnivores. Will all of them be able to survive this vicious world of tooth and claw?