The latest offering from the renowned German director Werner Herzog is inspired by a true story: an American bomber pilot, Dieter Denkler, is shot down in 1965 while on a covert bombing mission over Laos, targeting the Ho Chi Minh Trail. Captured and held in a tiny, remote jungle prison camp in Laos, most of the film revolves around the dynamics within the small group of prisoners, as the ingenious and dogged Denkler steels them for a daring escape. But as Denkler’s fast friend and fellow inmate Duane reminds him (a superb performance from Steve Zahn), the real prison is the jungle, and not the flimsy bamboo barricade surrounding the camp.

Despite the title and plot, Rescue Dawn is not really a Vietnam war movie, and certainly not an Iraq movie in jungle drag – and much the better for it. For all the accoutrements of war and moments of almost unbearable tension, the film is not a thriller either. There are no titillating torture scenes – the violence and torments inflicted on the prisoners are unexpected and arbitrary, and nor are there any gratuitous displays of racism against their captors. The film never loses the sense of Denkler’s isolation in a place both relentlessly hostile and utterly alien. The Laotian camp guards are brutal and inscrutable, the peasant villagers fearsome and terrified in equal measure; the jungle both overwhelmingly vast and impossibly claustrophobic, captured in close shots of impassable foliage and weird fauna.

There is no revelatory tearing away of transparently false American illusions. Denkler’s patriotism is simple and steadfast, though not particularly important to the film as a whole. More striking is Christian Bale’s inspired portrayal of Denkler’s determination and grit – neither ferocious nor overbearing, but absolutely unyielding. This is the focus of Herzog’s film: a close examination of prisoners on the verge of spiritual implosion, as they adjust to accommodate the leadership of the audacious new inmate, and confront the possibility of hope and freedom.

There is no redemptive or macho male bonding between brashly defiant Americans; the prisoners, crushed by years of captivity in a war that America denies it is even fighting, are shy and wary. The gestures of comradeship are gentle and measured, and the more poignant for it. There is too much exhaustion and claustrophobia for any frothing, swearing or eye-balling confrontations over the escape plan – and Denkler’s opponent is barely sane enough to warrant contempt or hatred. Denkler’s leadership involves not only plotting a brilliant escape, but also fortifying his comrades’ morale and fragile sanity – a dynamic amusingly captured in a scene where Denkler and Duane gently squabble over a game of ‘stack the fridge’, where the American prisoners take turns lasciviously fantasising over the food that awaits them in their imaginary fridges.