Once you jump back in time, you can never return. Lincoln Woodhouse knows this, but that doesn't keep him from trying. After all, who wants to live forever in a brutal land of scimitar-toothed cats and vengeful Neanderthals? Lincoln, Skyra, and the rest of the team escape by jumping forward 47,000 years. But the present isn't what it used to be. In this new timeline Neanderthals are not extinct, and the world is at war. With only enough equipment for two more time jumps, the travelers prepare to jump again before they get caught up in the conflict. Too late-the team is attacked and captured, and soon they find themselves amid an extraordinary society of spider-worshipping Neanderthals. Lincoln and Skyra, although from two very different worlds, deepen their unusual bond as they become embroiled in a daring plan to launch a revolution. In the midst of turmoil and deceit, they make a new friend-who may embody their future destiny.