Moscow, 1812

The story begins just before Napoleon's invasion of Russia and the burning of the city.  Hélène's husband Pierre, a wealthy middle-aged aristocrat is having a crisis, living a life of wine, philosophy and inaction. He is best friends with Prince Andrey, who has left to go to war. Andrey has recently become engaged to the young, beautiful countess Natasha Rostova. Natasha and her cousin Sonya arrive in Moscow to stay with an old friend of Pierre's and Natasha's godmother, Marya D., while Natasha waits for Andrey to return from the war. 

The next night Natasha is introduced to the Moscow society after an amazing performance at the Opera; there she meets Hélène's brother Prince Anatole, a young and handsome officer and, it turns out, a notorious rogue. Anatole's aggressive flirtations leave Natasha feeling confused.

Anatole, his friend Dolokhov, and Pierre go out drinking; they are met by Hélène, who taunts Pierre and flirts with Dolokhov. Anatole declares his intention to have the young woman he just met, although he is already married. Pierre finds his wife's familiarity with Dolokhov offensive and drunkenly challenges him to a duel, risking his life. Fortunately, and luckily, Pierre wounds Dolokhov, and Dolokhov misses Pierre; no one dies. Afterwards, Pierre reflects on his life. 

Hélène finds it amusing to encourage her brother's conquest of the young countess Natasha, which she knows would lead to Natasha's ruin. Hélène flatters Natasha and invites her to the ball that night, where Anatole seduces Natasha.

Anatole and Natasha make plans to elope, and Natasha breaks off her engagement with Andrey. Sonya finds out about the plan and tries to stop the elopement at any cost. That evening Anatole and Dolokhov plan for the elopement and call on their trusted famous troika driver, to take them to Natasha's house. However, they are thwarted at the last moment by Marya D. 

Natasha finally learns the truth about Anatole's marital status. After scolding a grief-stricken Natasha, Marya D. sends out a letter to Pierre asking him to come and help handle the crisis. Pierre finally learns that the object of Anatole's conquest is Natasha. Pierre gives Anatole money and orders him to leave Moscow; Finally, Pierre visits Natasha, who is distraught. He tells her that her young life is only beginning, and that if he were younger, more handsome and free, he would propose to her himself. After their meeting, Pierre experiences a moment of enlightenment while seeing the great comet of 1812 in the night sky.