Viggo Mortensen, the darkly handsome sword-wielding Aragorn from The Lord of the Rings movies, is on a different road. His latest film journey is a father-and-son story of survival in the direst of conditions - a post-apocalyptic world of death and destruction. He loves it.

"We were cold and miserable all the time," he said, talking about filming that took place outside Pittsburgh, in the post-Katrina ruins of New Orleans, and on the edge of lava at Mount St. Helens in Washington. "It was perfect. It's a lot easier to be cold than to fake cold."

The Road, the long-awaited and long-debated movie version of the Pulitzer Prize-winning Cormac McCarthy novel, finally arrives in local theaters today. Finished over a year ago, the releasing company, Dimension Films, chose to hold it out from last year's Oscar race, which was dominated by Slumdog Millionaire.

They thought they'd have a better chance this year, but it now finds itself being released on the same weekend as Avatar and entering an Oscar race in which The Hurt Locker and Up in the Air have taken the lead in early critics awards.

The Road has McCarthy's novel as a powerful base. He, after all, is the author of the Academy Award-winning No Country for Old Men (which, in comparison, seems light and breezy). It has a boy. It has a father. It has emotion. It does not have computer effects and spectacle.

It could emerge as good counterprogramming to Avatar - what might be called "a thinking person's alternative."

"We have no computerized effects," Mortensen said, proudly. "You see what we see. I have never been in a movie that is so influenced by its environment. We were near coal mines in Pennsylvania that had burned themselves out, leaving the countryside desolate and uninhabitable. We were in sections of New Orleans that had just been cleaned up after Katrina. The idea is that this is the universal world. No escape."

"I've been in movies that required physical action and horse work. I've been naked in movies. But emotionally nude is tougher. When everything is taken away from you and you must protect your son, you learn that possessions are not important."

The Road is about a father and son traveling across a world in which social conventions have been destroyed. Mortensen, who usually doesn't want to talk to the media, is eager to talk about this one. He calls it a secular spiritual journey.

"If you go honestly through this rough of a journey, you end up uplifted in the end. You learn that kindness is the greatest good in the world. That may sound simple, but most people haven't learned it yet. In the end kindness is most important. Not everyone 'loves' everyone else, even in these conditions. It's too easy for people to say they love. The more honest universal condition we need is kindness. We can still live together if we have that."

The Road also features Charlize Theron, Robert Duvall and Guy Pearce, but Mortensen's co-star is an Australian boy named Kodi Smit-McPhee, who was 10 during filming and is now 13.

Mortensen remembers a scene when he had to dip the boy's face into freezing water and he was sobbing, for real. The boy's father, also an actor, was on set, but stayed in the background as the camera kept rolling and Mortensen calmed and encouraged the boy to get through the scene.

"It was a turning point in our trust for each other," Mortensen said. "This is his movie. If his part doesn't work, my part doesn't work. It is a father-and-son story. He's a skinny little kid from Australia who, until now, had never even seen snow.... I felt protective of him, but the same way I would of any actor....

"He is an unusually mature boy for his age, and he understands the novel, which is more than you can say for a lot of adults. He wants his papa to be a good guy. He looks to the papa I'm playing for everything - for trust, for guidance. For survival. I felt that I was working with an equal."

Neither the film nor the book gives any reason for the apocalypse.

"The important thing," Mortensen said, "is the impact of fighting for survival. This is hope, not defeatism. We're not making a movie here about the end of anything."