Directed by Tay Garnett, starring Jean-Pierre Aumont and Gene Kelly, the film was partly based on Hans Habe's 1941 novel A Thousand Shall Fall.

Defeated by the invading Germans in 1940, Marshal Philippe Pétain signs a peace agreement and the troops surrender.

The men receive solace from Father Sebastian (Sir Cedric Hardwicke), a priest who was also in the army and who counsels them wisely, but he is eventually killed.

Duval (Hume Cronyn), collaborates with their jailers to get an easier life, and tries to recruit Paul (Jean-Pierre Aumont).

Part of his work entails helping Sergeant Berger smuggle perfume, silk garments and other luxuries for Lieutenant Schmidt from the hospital over the border into Occupied France.

The boy tells them the Americans have landed in North Africa and takes them to safety in René's home in Cardignan, where they meet other friends and plan to join General Cartier's army in the mountains.

Knowing they will return, René's mother leads the call to burn Cardignan to the ground to keep it out of German hands, and they head en masse into the mountains to join General Cartier.

The film ends with the final bars of La Marseillaise and the French flag bearing the Cross of Lorraine.

The film is partly based on the German refugee author Hans Habe's autobiographical Ob Tausend fallen (A Thousand Shall Fall) from 1941, about his war experiences fighting in the French Foreign Legion against his former homeland in 1940, being captured and then escaping from the German prison camp.