A journey's end. A bold plan. A final conflict. Skyra, Lincoln, and their companions have made their last time jump and are stuck 47,000 years in the past. For Skyra, it's home. For Lincoln and his team, it's fraught with menace-a land of claws, teeth, and stone weapons. Just surviving here is hard enough, but the group now must deal with the consequences of binary existence-two copies of the same person coexisting...