During World War I, a young lieutenant in charge of a small British mounted patrol in the empty Mesopotamian desert is shot and killed by an unseen sniper. This leaves the sergeant Victor McLaglen at a loss, as he had not been told what their mission is and has no idea where they are. Traveling north in hope of rejoining their brigade, the eleven remaining men push on until they reach a desolate oasis offering water, edible dates, and shelter.
During the night, one of the sentries is killed, the other seriously wounded, and all their horses are stolen, leaving them stranded. They bury the dead man and place his sword at the head of his grave. One by one, the remaining men are picked off by unseen assailants. Across the course of the ordeal, the men talk and reminisce and quarrel, yet they also confront their increasingly desperate predicament. In a bid to summon help, the sergeant orders two men chosen by lot to go on foot for aid, but they are captured and their mutilated bodies are returned to the oasis.
One man, Abelson, Sammy Stein, is suffering from heat exhaustion, and he spots a mirage that lures him toward danger, where he is cut down by deadly rifle fire. And a glimmer of hope appears when the pilot of a British biplane spots the survivors; the Aviator Howard Wilson lands the aircraft nearby, but despite frantic warnings, he is killed. After dark, the sergeant seizes the machine gun from the aircraft and, in a stark counterpoint to the earlier mercy of war, sets the plane alight as a signal to any friendly troops nearby.
Sanders, a religious fanatic, Boris Karloff gradually descends into madness and walks into the line of fire. Pvt. Morelli, Wallace Ford moved by a desire to save him, makes a valiant but doomed attempt; as he returns toward the sergeant, he is gunned down as well. In the end, only the sergeant remains; thinking he, too, must be dead, the six Arabs who have besieged the oasis press forward. He unleashes the plane’s machine gun to kill them all, and a British patrol riding up on the smoke from the burning craft pauses as the officer in charge asks, almost brusquely, where his men are. In silence, the sergeant gazes toward the graves, where six swords gleam in the sun, a somber testament to the cost of survival.
The quiet, relentless tension of the siege is carried by a small but vivid cast, each playing a role that underscores endurance, faith, and the fragility of life in a war-torn landscape.
