The story follows a mom and her three daughters getting prepared to travel to pick up the father of the girl returning home from military service. But on the way there is a tornado warning and the trip starts to get too dangerous so they stop on the highway and run to a house to take shelter. Nobody answers the door so they all get in to the cellar to wait out the storm. As the storm passes the family tries to make their way out only to realize that someone or something, not quite human, is holding them captive. Struggling to get out alive they soon find out they are not alone.