“Rescue Dawn”

But "Rescue Dawn" isn’t just director Werner Herzog revisiting the themes — man’s battle to overcome the pitiless, relentless forces of nature without going mad in the process — that have powered his most memorable movies, from "Fitzcarraldo" to "Grizzly Man."

This time, Herzog revisits the movie’s central character, German-born U.S. Navy pilot Dieter Dengler, whose ordeal as a prisoner during the Vietnam War inspired Herzog’s 1997 "Little Dieter Needs to Fly."

In that award-winning documentary, Dengler says he doesn’t think of himself as heroic — because "only dead people are heroes."

And Dengler is nothing if not determined to survive.

"Rescue Dawn" recounts his harrowing ordeal with grueling detail and relative (for Herzog) restraint, aided immeasurably by star Christian Bale’s equal commitment to re-creating Dengler’s POW tribulations.

From Hollywood blockbusters (such as "Batman Begins" and its upcoming sequel, "The Dark Knight") to artier fare, Bale inhabits his roles with an intensity that can be downright scary — especially when the project requires physical transformation. (To play the sleepless lead role in 2004’s "The Machinist," Bale reportedly lost 63 pounds — and wanted to lose more, but production officials stopped him, fearing permanent damage to his health.)

Bale undergoes similar physical deprivation here, metamorphosing from hearty all-American pilot to wizened prisoner. (In the process, Bale’s cheekbones emerge so sharply they resemble axe blades.)

It’s an impressive physical transformation, to be sure, but it pales in comparison to the psychological tests Dengler endures to become one of only seven American POWs ever to escape Viet Cong imprisonment.

Inspired to become a pilot during his World War II boyhood in Germany’s Black Forest — when an American flyer zoomed so low the boy could look him in the eye — Dengler joins his Navy buddies in 1966 aboard an aircraft carrier, laughing heartily as they watch a hokey instructional film demonstrating jungle survival tips.

They’ll never need them — even though they’re about to embark on a secret (and illegal) bombing mission.

But Dengler’s shot down over Laos. Refusing to bail out, he crashes in his plane — and is captured, then tortured, then marched to a Pathet Lao internment camp.

The enemy commander gives him an opportunity to go free — provided Dengler signs a paper condemning the U.S. and its imperialist policies. But little Dieter’s not about to renounce the country that gave him his wings.

So he winds up in a bamboo pen with six other POWs — some CIA agents, some Southeast Asian allies — who’ve been in captivity for more than a year, as their emaciated bodies and broken spirits reveal.

Undeterred by a starvation diet of worms and rice, Dengler hatches an ingenious escape plot, employing a variety of techniques he picked up in a German tool-and-die factory to fashion crude weapons.

Convincing his fellow inmates to share his enthusiasm is another matter. Dengler must battle the dispirited Gene (a twitchy, jittery Jeremy Davies) for the support of his fellow prisoners, especially Duane (Steve Zahn, burying his customary comedy instincts beneath a blanket of weary, wary dread) if they’re ever going to get out of there.

And when they do (with Dengler in charge, there’s never any doubt), additional obstacles loom, from armed guerillas to the dangers of the jungle itself.

Dangerous, yes, but beautiful, too. And, amid the pulse-pounding suspense of the escape, "Rescue Dawn" takes time to ponder the irony of terror and wonder existing side-by-side. (As they so often do, especially in wartime — and in Werner Herzog movies.)

Those who’ve seen "Little Dieter Needs to Fly" (which played the fledgling CineVegas film festival) will miss some of the psychological depth Dengler himself provided when he and Herzog returned to the jungle to re-create his great escape.

Yet, in some ways, the fictional version seems even more realistic than the documentary, in part because Herzog has eliminated some of the documentary’s most outlandish details. (As when Dengler imagines a bear — symbolizing death — stalking him through the jungle. Or maybe Herzog got bears out of his system in "Grizzly Man.")

As he did in the aforementioned "Grizzly Man," Herzog resists the temptation to embellish his tale. Confident in the elemental power of Dieter Dengler’s brush with death, he knows "Rescue Dawn" doesn’t need it.

Besides, he already knows the story.