Back in France, sergeant-major Galoup (Denis Lavant) remembers the time in the desert, where he led his men under the command of Bruno Forestier (Michel Subor). His life there consisted mostly of routine duties like supervising the physical exercise of his men.
One day, his troop is joined by Gilles Sentain (Grégoire Colin), whose physical beauty, social skills, and fortitude make Galoup envious. As in the novel, repressed homosexual feelings on the part of Galoup are hinted at.
When Sentain helps another soldier, violating previous orders by Galoup, Galoup sees a chance to destroy Sentain. As a punishment, he drives him out into the desert to make him walk back to the base. But Sentain does not return—either because he does not want to or is lost—and almost dies near a salt lake.
Even though Sentain is later found and rescued by natives, Galoup is sent back to France by his commander for a court martial, ending his time in the Foreign Legion. The final scene suggests the possibility of his suicide.