At one of her soirees, Anna Scherer suggests Princess Maria Bolkonskya to Vasili Kuragin as a suitable match for his wayward son Anatole. Also bending Vasili's ear is Princes Drubetskoya, who is intent on securing a place in the Imperial Guard for her son Boris. The newly legitimized Pierre Bezuhov makes a poor impression at the reception, but is pleased to catch up with his old friend, Prince Andrei Bolkonsky, who is Maria's brother. Later that evening, Pierre learns that Andrei is unhappy in his marriage. Andrei's wife, Lisa, believes that his feelings for her have changed since they married. She also harbors fears about her unborn child and Andrei's determination to go to war. Andrei plans to leave for Austria after he has installed Lisa at Bald Hills - the country estate where both his father and sister live...

Twenty thousand men have died at Austerlitz and Marshal Kutuzov has written to Prince Bolkonsky to inform him that Andrei is among them. Maria is afraid to pass on this news to Andrei's wife, Lisa, as her pregnancy is at an advanced stage. There is a happier mood at the Rostovs when Nikolai arrives home bringing Denisov with him. While Natasha is no longer infatuated with Boris, Sonya is still in love with Nikolai, but wants him to be free if that is his wish. Pierre, now married to Helene, is just about the only man in Moscow who is unaware that his wife has taken a man called Dolohov as her lover. Dolohov is introduced to the Rostov family; he feels that it is high time he was married and immediately shows an interest in Sonya....

Pierre learns that Dolohov is Helene's lover and, at a banquet hosted by Count Rostov in Kutuzov's honor, he is deliberately provoked by his rival. When Dolohov announces aloud that after the banquet he has a date with a rich pretty married woman, Pierre finally loses control and challenges him to a duel. The duel takes place the next day and Pierre seriously wounds Dolohov. After Helene learns what has happened she asks Pierre for a separation, telling him that being his wife has been an embarrassment to her. Denisov, who has had his eye on Natasha, proposes marriage. She like Denisov but does not wish to marry him. A chance meeting at a post-house leads a desolate Pierre to a new way of life. Meanwhile at Tilsit, Napoleon and the Tsar prepare to sign a truce....

Andrei is weary of life, but meeting Natasha at the Rostov family home prompts him to reappraise his feelings. Lieutenant Berg, who is set to marry Vera Rostov, discusses the question of her dowry with the Count. Maneuvered into offering a hundred thousand rubles, the Count becomes worried about the family's financial security. When he tells the Countess that he has decided to take up a government post at Petersburg, she suggests that they should all go there for a last fling before they begin to cut down on their spending. Once at Petersburg, the Rostovs attend a grand ball at which the Tsar is the guest of honor. Pierre and Helene are there, as is Andrei Bolkonsky who, at Pierre's suggestion, asks Natasha to dance with him....

Leaving the Countess behind in Petersburg, the Count, Natasha and Sonya return to Moscow. Natasha's godmother, Maria Dmitrievna, is also staying with them. She informs Natasha that Andrei's father and sister are in Moscow and that she should call on them. The visit does not go well, primarily because the old Prince refuses to see anyone, causing both Princess Maria and Natasha to feel ill at ease. Natasha longs for Andrei to come back and weeps for him once she is home again. While enjoying various entertainments with her father and Sonya, Natasha meets Anatole Kuragin for the first time. As soon as the opportunity arises, he tells her that he has fallen in love with her. Reticent at first, Natasha soon succumbs to his charms....

Marshal Berthier tries to persuade a reluctant Napoleon that they should leave Moscow and return to France, while Marshal Davout believes that they should sit out the winter there. Napoleon himself wishes to march on Kutuzov and his army in Kalouga but is forced to order a retreat. The Russian prisoners, who include Pierre and Karatayev, are forced to march with the retreating French army, pushing their carts along through the snow. Any prisoners who are unable to walk any further or are too sick to carry on are shot dead. Karatayev becomes unwell and Pierre feats that he will not survive. The retreat is observed by Denisov and Dolohov who intend to attack the French once they have learned how many there are and how they are defended. Petya arrives and begs Denisov that he be allowed to join the attacking party....