Fans of Cormac McCarthy’s “The Road” will find much to enjoy in this sombre and nerve-wracking postapocalyptic horror film, directed and co-written by Jim Mickle. The story is centered on a Southern teen-age boy (Connor Paolo) who, after his family is killed by blood-sucking flesh eaters, is taken under the wing of a man called Mister (the co-writer Nick Damici) and learns the art of a good staking. Together they travel north in search of a safe haven. The performances are terrific; Damici has a craggy, commanding Charles Bronson-like authority, and Paolo, though sensitive, leaves his character open to tougher, more violent possibilities. The mayhem is beautifully composed and, as the pair travels through small towns filled with survivors and with marauding bands of killers, the film’s rural, disembowelled landscape turns nature itself into an enemy.