After a hiking trip goes terribly wrong and an ancient ritual causes the earth to open up beneath their feet, Allen, Jenna, Ana and Blake awaken to find themselves in a demonic world and their respective siblings nowhere to be found. From dinosaurs to a deadly fog and a famine so severe that kin-eaters are on the rise, can Allen, Jenna, Ana and Blake survive long enough to reunite and claw their way out of hell itself? Or will they literally die trying...?