This movie is a story about French railroad workers who were part of organized resistance during the German WW2 occupation.
Acts of slow down and sabotage announce that French railway men don't accept the presence of the "Boche" willingly. . Trains are misdirected, rails are damaged. Jews are helped to escape. Resistance fighters and their messages are smuggled from place to place. We learn that there are "good guys" and "bad guys" among the French rail employees. The "trade craft" of espionage is practiced as French rail workers fight the twilight struggle against collaborators and the German oppressors. Not every character is who he seems. After the D-Day landings the tempo of resistance escalates. Tension mounts as the Germans desperately try to bring tanks and men into battle to throw back the invaders. The light infantry of the Maquis fights a pitched battle with an armored rail convoy of Germans on their way to Normandy. After initial German successes the Resistance wins, but at a high price. French morale is the intended object of this record of heroic resistance against odds. The black and white of the film is matched by the "black and white" of collaborators and "La Resistance."