During 1st WW, two French officers are captured. Captain De Boeldieu is an
aristocrat while Lieutenant Marechal was a mechanic in civilian life. They
meet other prisoners from various backgrounds, as Rosenthal, son of
wealthy Jewish bankers. They are separated from Rosenthal before
managing to escape. A few months later, they meet again in a fortress
commanded by the aristocrat Van Rauffenstein. De Boeldieu strikes up a
friendship with him but Marechal and Rosenthal still want to escape...