The United States Army is conducting a fighting retreat. A high bridge spans a ravine on the Bataan Peninsula. After the army and some civilians cross, a group of thirteen hastily assembled soldiers from different units is assigned to blow it up and delay Japanese rebuilding efforts as long as possible. They dig in on a hillside, setting up heavy machine guns in sandbag fortifications. They succeed in blowing up the bridge, but their commander, Captain Henry Lassiter, is killed by a sniper, leaving Sergeant Dane in charge.