French resistance fighters try to stop the Nazis from taking a trainload of art treasures to Germany.

As Allied forces approach German-occupied Paris in the summer of 1944, a Wehrmacht officer, Col. Franz von Waldheim, receives orders from Göring to assemble the art treasures of the Jeu de Paume Museum and transport them to Germany. Mademoiselle Villard, curator of the museum, informs the Resistance of the plan and tries to persuade Labiche, area inspector of French railways, to intercept the priceless cargo. Labiche, however, is more concerned with saving lives than in preserving art, and he devotes his energies to sabotaging an armaments train. While Allied bombs are destroying the munitions, Papa Boule, an old railwayman, succeeds in burning out the engines of the train bearing the art treasures but pays for his act with his life. The enraged von Waldheim places Labiche in charge of moving the art train out of Paris. Labiche, now won over to the side of the Resistance mainly through the influence of a widowed hotelkeeper, Christine, arranges a complicated series of strategems that lead the Nazis to believe the train has passed into Germany while, in reality, it has merely been shuttled around Paris and returned to its original depot. Upon discovering the deception, von Waldheim places French hostages on the train and orders it moved. As Labiche once more intervenes by having it derailed, von Waldheim has the hostages shot; but his own men panic and join the retreating Wehrmacht. Left alone, the two equally obsessed men face each other. Labiche kills von Waldheim and walks slowly away, leaving scattered paintings on the tracks.