Dazed, bloodied and speechless with trauma, Sarah Carter emerges alone from the Appalachian cave system where the events of the Descent took place. Local sheriff Redmond Vaines forces her back underground to help the rescue team which is desperately searching for her five missing girlfriends. As the team moves deeper into the caves, Sarah's flashes of fractured memory intensify and she begins to realize the full horror of the would-be rescue mission. Only Sarah knows the terror which lurks in the shadows of the caves. But they are about to encounter a new tribe of crawlers - inbred, deformed and even more viciously feral than those Sarah faced before.