Viggo Mortensen, left, and Kodi Smit-McPhee play a father and son in the film version of Cormac McCarthy's post-apocalyptic novel The Road. (Macall Polay/2929/Dimension Films)

In a decade full of apocalyptic visions and survival tales, Cormac McCarthy's The Road has been among the most potent and moving. The 2006 novel, lovingly rendered in John Hillcoat's new film, takes a well-worn sci-fi scenario and re-shapes it into a sombre meditation on morality, faith and the power of love.

The Road is a sombre meditation on morality, faith and the power of love.

Viggo Mortensen stars as McCarthy's unnamed protagonist, a father making his way across the bleak, blasted landscape of a posthumous America, in the company of his young son (Kodi Smit-McPhee). Pushing their few belongings in a shopping cart, sleeping under a tarpaulin and scrounging for food, the Man and Boy could be homeless figures in any modern big city.

That poignant parallel is just one of the ways The Road looks less like a futuristic fable and more like a picture of our present decay sharply accelerated. The abandoned houses, churches and gas stations that the two visit recall the derelict buildings that stud the U.S. rust belt. When father and son come upon an eerily empty suburb, I was reminded of documentary footage of New Orleans' Lower Ninth Ward in the wake of Hurricane Katrina. This is truly Apocalypse Now.

McCarthy and Hillcoat don't specify what kind of disaster has laid waste to the world, but what remains is a bone-chilling hell. The charred skeletons of trees stand against sunless skies and a blanket of ash covers every exposed surface like grey snow. Earthquakes and fires alternate with drenching rains. Animal life has all but disappeared. Civilization, meanwhile, has devolved to the brutally primitive. Food is scarce – every shop and pantry has been raided. Savage gangs roam the highways, hunting and eating weaker human beings. The Man and Boy spend each day trying to fend off starvation and avoid the cannibals as they head south toward the coast – a vague, possibly pointless goal that has become, in the Boy's mind, a promised land.

Charlize Theron co-stars in The Road. (Macall Polay/2929/Dimension Films)

Born in Australia and raised in Canada, Hillcoat's previous credits include the acclaimed 2005 Outback western The Proposition, penned by British rocker-cum-writer Nick Cave. (Cave and Warren Ellis provide The Road's spare, piano-based score.) The Proposition mined the same brutal-but-lyrical vein as McCarthy's Wild West masterpiece Blood Meridian, suggesting Hillcoat had the right sensibilities to bring The Road to the screen. The film has its ugly and horrifying moments, but also a seared beauty – Javier Aguirresarobe's monochrome cinematography recalls the photos of Ed Burtynsky – and a great tenderness.

As the Man, a gaunt Mortensen — his piercing eyes staring out of a grizzled, dirt-creased face — is like a hunted animal fiercely protecting its young. We watch him gently washing the Boy's hair and reading him bedtime stories, but also teaching him how to commit suicide with a revolver rather than be captured alive. As his son, Australian actor Smit-McPhee (who was 11 when the film was shot) has a touching vulnerability – he wears his late mother's oversized tuque and clutches a little toy elephant, sad vestiges of innocence in a harsh and perilous world.

It turns out the Boy is also a repository of those things that elevate humanity above the bestial. The Man has assured him that they are "the good guys," who "carry the fire inside." Later, as that fire begins to die in the father, it flares up in the son, who stubbornly displays a compassion for others. The sense is that a fragile flame of decency has been passed between generations, a little flicker of hope for humankind.

Joe Penhall's adaptation is scrupulously faithful to the novel, but it doesn't adopt McCarthy's occasionally portentous biblical tone. It also gives more weight to the character of the Woman – the Man's wife and the Boy's mother, seen here in a series of flashbacks/dreams. Played with passion by Charlize Theron, she is no longer the bitter defeatist of the book, but rather a strong, pragmatic pessimist. She rejects her husband's heartbroken pleas to accompany him and the Boy, but then instructs him to go south if they're to have any chance of survival.

There are other small but vivid performances from a choice cast that includes Guy Pearce, Molly Parker, Michael Kenneth Williams (Omar of The Wire) and, most strikingly, Robert Duvall. As an elderly fellow traveller, his eyes bleared by cataracts, his feet shod in cardboard, Duvall is virtually unrecognizable. In the space of a few minutes, he conveys both the gravity of a prophet of doom and the pathos of a decrepit grandfather.

The movie, however, belongs to Mortensen and Smit-McPhee, whose parent-child dynamic is natural and unsentimental. Mortensen's Man shows his love for his son less through words than actions, including such simple gestures as giving him a lone can of Coke discovered in a plundered shopping centre. It's the Boy's first taste of that once-ubiquitous beverage but, tellingly, he insists on sharing it with his dad. I defy any parent of a young child to watch scenes like that without choking up a little.

For filmgoers who know McCarthy via the Coens' dark Oscar winner No Country for Old Men, it will come as no surprise that the author takes a dim view of humanity's fate. The revelation in The Road is that this tough old nihilist also has a heart.

The Road opens Nov. 27.

Martin Morrow writes about the arts for CBC News.