In a Japanese prisoner-of-war camp in Burma in 1943 a battle of wills rages between camp commander Colonel Saito and newly arrived British Colonel Nicholson. Saito insists that Nicholson order his men to build a bridge over the river Kwai, which will be used to transport Japanese munitions. Nicholson refuses, despite all the various "persuasive" devices at Saito's disposal. Finally, Nicholson agrees, not so much to cooperate with his captor as to provide a morale-boosting project for the military engineers under his command. The colonel will prove that, by building a better bridge than Saito's men could build, the British soldier is a superior being even when under the thumb of the enemy. As the bridge goes up, Nicholson becomes obsessed with completing it to perfection, eventually losing sight of the fact that it will benefit the Japanese. Meanwhile, American POW Shears, having escaped from the camp, agrees to save himself from a court martial by leading a group of British soldiers back to the camp to destroy Nicholson's bridge. Upon his return, Shears realizes that Nicholson's mania to complete his project has driven him mad.