A time gate.
A team of fossil-hunters.
A desperate fight to survive.

Park Ranger Hannah Kates thinks that guiding a class of gifted high school science students through a hunt for fossil mammal bones in the Badlands will be a tough day's work. But Hannah is about to learn a new definition for the word "tough," when a rock slide at the fossil site uncovers a portal through time. The fossil hunters are caught in it and swept back to an era when giant predator mammals roamed the earth.

How can they return home? And when they are so outclassed by the monstrous animals, when they have no weapons, how can they survive on their wits and courage alone?

The exciting adventure begins.