In 1812, Napoleon's army controlled most of the European countries. Among the few that remained unconquered, Russia planned to join forces with Austria for a desperate resistance. Duke Andrei (played by Mel Ferrer) was a Russian officer with great ambitions. However, Andrei's close friend Duke Pierre (played by Henry Fonda) showed no interest in the war. He inherited his father's fortune just before his death and married the noblewoman Helen (played by Anita Ekberg), but soon after their marriage, they discovered they were incompatible and separated. After Andrei's defeat in battle, he was released and returned home to see his wife, who died in childbirth. A few months later, Pierre went hunting with the Rostov family and invited Andrei along. Andrei fell in love at first sight with the Count's daughter, Natasha (played by Audrey Hepburn). Not long after, Natasha accepted Andrei's proposal, but Andrei quickly returned to the military. Helen's brother Anatole took advantage of the situation and tricked Natasha into falling in love with him, encouraging her to elope with him. When the Russo-French War began, Natasha encountered the severely wounded Andrei, who forgave her betrayal before he died. After the war ended, Pierre returned to Moscow and united with Natasha.