As the Rostovs flee their estate, they encounter wounded soldiers on the way and decide to take them with them. On their journey, they find a badly injured Andrei lying by the side of the road and also bring him along.
Pierre, still seeking redemption for his past mistakes, disguises himself as a peasant and sneaks into Moscow seeking to assassinate Napoleon. However, he is quickly caught by the French and taken prisoner.
Meanwhile, the French army is forced to retreat from Moscow due to the city being set ablaze by the retreating Russians. Pierre is marched with the Grande Armée for several months, experiencing the brutal conditions of war firsthand.
On their retreat, the French encounter the Russian army led by General Kutuzov in the Battle of Krasnoi. The Russian army emerges victorious, but not before losing many soldiers, including Andrei.
Andrei is recognized by his fellow soldiers and taken back to his estate, where he eventually dies from his injuries. In his final moments, he forgives Natasha for her past infidelity and asks for her forgiveness in turn.
Natasha, now widowed, reunites with Pierre who has been freed by a raiding party. They finally confess their love for each other and get married as Moscow is being rebuilt after the war.