An American Family goes on a vacation . During their trip , they begin to notice that something strange is happening to the people around them . They are starting to sound and look crazy , attacking their own kind for no apparent reason and even devouring one another like wild beasts . At first glance it seems like a game of zombies but in fact this is no game - this has become their new reality , one in which fear and death reign supreme . The family manages to escape in panic and soon they realize that the only way they can manage to stay alive is to defend themselves by any means . Through their struggle for survival they encounter people from different backgrounds and are forced to band together for one purpose - Survival .