The Time Warp Trio is going back in time, all the way to the Stone Age, where there aren't any math problems. But there are plenty of other problems to keep Sam, Joe, and Fred on their toes, including a tribe of hostile cave women, a hungry-looking saber-toothed tiger, a bone-rattling earthquake, and a woolly mammoth who wants to turn them into toe-jam. But worst of all, how can The Book get them back home again when writing hasn't even been invented yet?
