The film is set before, during, and after the Great War in several different parts of France, Austria, and Germany. Jules is a shy writer from Austria who forges a friendship with the more extroverted Frenchman Jim. They share an interest in the world of the arts and the Bohemian lifestyle. At a slide show, they become entranced with a bust of a goddess and her serene smile and travel to see the ancient statue on an island in the Adriatic Sea.
After encounters with several women, they meet the free-spirited, capricious Catherine, a doppelgänger for the statue with the serene smile. The three become inseparable. Although she begins a relationship with Jules, both men are affected by her presence and her attitude toward life. Jim continues to be involved with his girlfriend Gilberte, usually seeing her apart from the others. A few days before war is declared, Jules and Catherine move to Austria to get married. Both men serve during the war, on opposing sides; each fears throughout the conflict the potential for facing the other or learning that he might have killed his friend.
After the wartime separation, Jim visits, and later stays with, Jules and Catherine in their chalet in the Black Forest. Jules and Catherine by then have a young daughter, Sabine. Jules confides the tensions in their marriage. He tells Jim that Catherine torments and punishes him at times with numerous affairs, and she once left him and Sabine for six months.
She flirts with and attempts to seduce Jim, who has never forgotten her. Jules, fearful that Catherine might leave him forever, gives his blessing for Jim to marry Catherine so that he may continue to visit them and see her. For a while, the three live happily with Sabine in the chalet, until tensions between Jim and Catherine arise because of their inability to have a child.
Jim leaves Catherine and returns to Paris. After several exchanges of letters between Catherine and Jim, they resolve to reunite when she learns that she is pregnant. The reunion does not occur after Jules writes to tell Jim that Catherine suffered a miscarriage.
After a time, Jim runs into Jules in Paris. He learns that Jules and Catherine have returned to France. Catherine tries to win Jim back, but he rebuffs her, saying he is going to marry Gilberte. Furious, she pulls a gun on him, but he wrestles it away and flees. He later encounters Jules and Catherine in a famous movie theater, the Studio des Ursulines.
The three of them stop at an outdoor cafe. Catherine asks Jim to get into her car, saying she has something to tell him. She asks Jules to watch them and drives the car off a damaged bridge into the river, killing herself and Jim. Jules is left to bury the ashes of his friends in the Père-Lachaise Cemetery columbarium; Catherine wanted her ashes to be scattered in the wind from a hilltop, but at the time it was not legal.[5]
