A group of four teenage friends become trapped in a Mexican border tunnel where they fall prey, one-by one, to tortured ghosts who haunt it.A group of four teenage friends become trapped in a Mexican border tunnel where they fall prey, one-by one, to tortured ghosts who haunt it.A group of four teenage friends become trapped in a Mexican border tunnel where they fall prey, one-by one, to tortured ghosts who haunt it.