Alaska is a wild and unpredictable land. Cradled along the Ring of Fire, hundreds of earthquakes occur every day. Parachuting in on a joint night operation, members of the 4th Brigade Combat Team Airborne find themselves blown off course. The U.S. Army soldiers are adaptable, so they head to the original drop zone. En route to their destination, a cataclysmic earthquake shatters their world. Plunged into a gaping fissure that just might swallow them up, the soldiers struggle to survive the unbridled earth. Crawling out from the bowels of the deep fissure, the soldiers of the 4th Spartan Brigade find themselves shoved into the arms of the Ice Age, 23,000 years ago. They will use all their training and cunning to survive this wild new land.