Three British paratroopers are cut off from their unit and are lost behind enemy lines. Sheltering in a deserted farmhouse, they are awaiting the return of their Sergeant who has ventured out in an attempt to locate their unit. The three soldiers are Tom, a world-weary cynical veteran, John, a middle-class educated thinker who despises war and Cliff, an eager soldier who loves his work. All three are highly trained professional killers who, regardless of their thoughts, do not hesitate to perform their duties.
Two German soldiers approach the farmhouse and the paratroopers dispatch them both. The second of the enemy attackers is stalked by the paratroopers who virtually toy with their victim before John kills him, finishing the man off up close, although the experience renders him sick. As the three men eat a meal, they are surprised and captured by a third German named Helmut, a paratrooper like themselves. The British soon turn the tables and capture Helmut but the latter, who speaks English, manages to manipulate his captors into keeping him alive. The group leave the house in search of their Sergeant whom they eventually find dead in the woods, his throat cut. The men continue on, trying to find their way back to Allied lines. They come across a farmhouse, where a trio of Germans are sheltering. The paratroopers cautiously approach and shoot them, only to find that the Germans are already dead.
After spending the night in the house, the group continues their walk back to the British lines, only to run into a German patrol. In the ensuing battle, all of the Germans are killed but Cliff is fatally wounded. John and Tom reach the frontline, taking their prisoner Helmut with them but nearby British troops mistake them all to be German and open fire, mortally wounding Tom. Both injured themselves, John and Helmut take cover in a muddy ditch. There, John decides to kill Helmut with a small skewer he has always carried with him. Delirious with exhaustion and trauma, John staggers into the open, yelling that he is a pacifist before the British troops open fire again, shooting him dead.