Based on the effective, if slightly overrated, Pulitzer Prize-winning novel by Cormac McCarthy, "The Road" has been faithfully brought to the screen by director John Hillcoat and screenwriter Joe Penhall with all the visual perks that the medium can offer. Stark and almost ceaselessly funereal, the story goes that the earth is on its last legs (the particulars are unnecessary and, thus, never discussed). The skies are constantly ashen and gray. Smoke billows from once-thriving towns that are now nothing but a heap of dilapidating buildings, broken windows and rubble. Animal and plant life cease to exist. Food is a rare, precious commodity to come by. And as for humans—well, let's just say that most of the few left have turned to cannibalism for their own survival. Out of the barren landscape walk a father (Viggo Mortensen) and his young son (Kodi Smit-McPhee), two of the few "good guys" still around, on a voyage south to the ocean's edge. What do they hope to find there? It is hard to say. Possibly other life, the kind that doesn't want to have them for dinner. Or maybe they just want a sign of hope to prove to them that life is still worth living. All the same, the father holds onto a gun with two bullets in it, and instructs his boy on the right way to cleanly and fatally shoot himself through the mouth in case their options run out.

As a book, "The Road" consists mostly of brief but telling dialogue exchanges between the father-son protagonists placed in between generous, ponderous stretches of prose describing the dire environment of a post-apocalyptic planet. In the wrong hands, this intimate human tale might have been beefed up with careless action set-pieces and an onslaught of CGI. That is precisely what its misleading trailers suggest. Fortunately, director John Hillcoat stays true to what is a dark, but in many ways strangely beautiful, tonal poem. Special effects are used so seamlessly that it is difficult to tell what was shot practically and what was digitally added in post-production. The portrayal of a cold, dying world is immersive and frequently chilling, isolation deeply felt as man and boy wander down highways and through towns and neighborhoods where life no longer exists and only the ramshackle remains of homes, stores and abandoned automobiles signal a past that no longer is.

Flashbacks of the man and his wife (Charlize Theron) before the end of times arrive are fleeting, giving way to the tragedy that befalls them, just as it befalls the entire population. The wife gives birth to the boy, but can hardly stand the idea of bringing a new human being into such a futile world. She ultimately loses faith and wanders off into the darkness one night, a suicidal gesture that leaves the man and boy by themselves. This is the catalyst for their journey—it is too dangerous to stay in one place for too long—and the film's impact is strengthened through their unsentimental parent-child bond. Because dialogue is decidedly minimal, much of the love and care that come from them is captured through their actions. The way, for example, that the father gives the boy a can of Coke that he finds—it is possibly the first time he has tasted a soft drink—and the way that the boy insists his starving papa have a drink, too. Or the way that the father will do anything at all costs when his boy is put into immediate danger by a knife-wielding wanderer. Or the look of horror on the boy's face when his dad won't stop coughing, and he spots a puddle of blood he has spit up. "The Road" is a morose experience, almost guaranteed not to end in a happy-go-lucky manner, but it is the humanity that these two characters hold onto that keeps things from growing unbearably dour.

In what is a primarily two-actor showcase, Viggo Mortensen (2008's "Appaloosa") and newcomer Kodi Smit-McPhee share a comfortable and trusting chemistry. Mortensen has obviously put himself through the physical wringer—unclothed shots of his gaunt, malnourished body remind of Christian Bale in 2004's "The Machinist"—while Smit-McPhee, affectless, emotes with a frequently heartbreaking honesty. That the Australian Smit-McPhee, eleven at the time of filming, puts on an American accent is all the more impressive, and may be the reason why he comes off a little wobbly in selling the odd line of dialogue. Making a big impression with only scarce screen time, a nearly unrecognizable Robert Duvall (2008's "Four Christmases") is a haunting force as a withering old man the father and son meet on the road and lend a hand to. Charlize Theron (2008's "Hancock") also leaves a memorable imprint as the boy's ill-fated mother, a woman whose reasons for living are gradually outweighed by reasons to give up. Long after her character is gone, Theron's formidable work leaves behind a shadow that casts on Mortensen's and Smit-McPhee's faces and psyches.

When judged against one another, the literary version of "The Road" is able to delve into greater detail, aided by Cormac McCarthy's lyric pen, but the cinematic version may be a step above from a dramatic standpoint. There are a few debits—for one, a late-in-the-movie sign of life the man and boy spot is at once miraculous and not quite as powerful as it was in the book, when the father saw a single fish swimming in a creek—but the ending, which came off as too neat, tidy and out-of-left-field in the book, seems a tad more organic on film because director John Hillcoat has slyly been foreshadowing it throughout. Still, had it been altered from the novel's conclusion, it would have stood as the one element where change was welcomed. With "The Road," there are no aliens, no otherworldly creatures, and no futuristic flourishes, and that's a good thing. The picture glimpses what it might really be like if the earth went to hell. As shattering as the sights are, turning away is out of the question.