In France during World War I, Marthe waits for her husband, Jacques, while he fights on the front lines. Marthe then begins a tempestuous affair with 17-year-old François, with whom she had a dalliance before marrying Jacques. Jealous François struggles with the fact that Marthe is married, while she tries to prove her devotion to her young, hotheaded lover. Things become even more complex when Marthe becomes pregnant with Jacques' baby.

Fanfan is a young handsome peasant. He joins the army to escape marriage because a gypsy girl predicted he will get glory and the king's daughter as a wife. But the gypsy girl was in fact Adeline, the daughter of the recruiting officer. Once he has discovered the stratagem, Fanfan refuses to forget this dream and decides to fulfill the destiny of the fake prediction.