As Napoleon's army marches towards Russia, Pierre Bezukhov visits his dying father, unaware that his relations are scheming to have him disinherited, while Prince Andrei Bolkonsky leaves his wife behind as he prepares to join the war.

As Nikolai Rostov and Andrei prepare for battle, a determined Prince Vassily Kuragin tries to forge a bond between Andrei's sister, Princess Marya, and his son, Anatole, while Pierre finds his new married life difficult.

Despite his nervousness, Pierre must keep his appointment with Dolokhov, the effects of which lead him on a new path. Meanwhile, Natasha and Sonya Rostova both receive unexpected proposals, and Andrei tries to forget his grief.

After proposing to Natasha, Andrei agrees to his father's proviso that he go abroad for a year, leaving Natasha emotionally vulnerable, while Nikolai declares his love for Sonya, much to his mother's regret.

The Rostovs leave Moscow as the French army draws near, leading to an unexpected reunion, Pierre performs a heroic act which has repercussions for both he and his wife, while Sonya makes an important decision.