Tried and convicted for his crimes, Sean Barrow is sent into temporal exile—banished to a time so far before recorded history that there is no chance that he, or any other criminal sent back, has any chance of altering history. Now Sean must find a way to survive more than 200 million years in the past, in a world populated by monstrous creatures that would rend him limb from limb if they got the chance. And that’s just his fellow prisoners. The dinosaurs are almost as bad.