Bernard Lefrancois is a prosperous farmer on the River Marne, while his neighbor is impoverished. Lefrancois objects strongly to the romance between his son and the neighbor's daughter, but it continues in secret. WWI begins and the son becomes an aviator with the French army, and the unwed girl presents Lefrancois with an unexpected grandchild. The German army occupies the area, and the girl is serving France as a spy and securing information needed by the French to drive out the Germans. While his son is engaged in air-combat against the Germans, and the unwed mother of his grandchild is serving as a spy against their country's enemy, Lefrancois also joins the battle as a soldier.

Lieutenant Varnière, responsible for discovering the cause of the death of two officers in Algeria, unmasks the assassin in the person of a Russian who lives with three women. He falls in love with one of them and runs away with her while the Russian is killed by a devoted servant.

In a small town in Spanish Morocco, old Ricardo, who runs a café, lives with his daughter, Conchita. She believes that Ricardo is her father. In reality, he took her in at the age of eighteen months in a douar abandoned during the conquest. One day a Berber chief, Tamar, sees Conchita, tells her that she is from his tribe and wants to take her away. She rejects it, then accepts later to find that Muslim civilization is incompatible with the Christian training she received. She escapes and succeeds in obtaining forgiveness from Tamar. A French officer from the Intelligence Service offers to collect it.

In the Sahara, Algeria, the leader of the Tuaregs, Aftan, saves a girl from the hands of a caravan of pillars. Madeleine falls in love with her savior and their marriage is decided. But Aftan understands that he will never be assimilated with Europeans, and he goes back to find the beautiful poet Dassine whom he had loved before.