"Then: First Lieutenant Sean Elliott and nine other mixed-service U.S. soldiers on a convoy in Afghanistan suddenly found themselves and their MRAP vehicle thrown back to Earth's Paleolithic Age. And they were not alone. Displaced Romans, Neolithic Europeans, and more showed up as well. Some would be allies. Some became deadly foes. Now: Scientists from an almost unimaginably far future need the survivors' advice and support to reconnoiter and ultimately...