As the French army marches into Moscow, chaos descends on the city.

The Rostovs are forced to flee. Natasha is shocked by an unexpected fellow traveller while Sonya is asked to make a huge sacrifice for her family. Traumatised by his experience of battle, Pierre resolves to stay behind and stop Napoleon himself. In the process, he meets a stranger who changes his outlook on life forever.

Napoleon invades Russia and preparations begin for another great battle against him.

As the French army marches east, Marya is terrified to discover that her family is in danger and her father is refusing to listen.

Natasha falls ill and Pierre helps care for her before making a decision that opens his eyes to the horrors of war. Andrei finds he cannot forgive Natasha, and vows to take revenge on his rival. Meanwhile, Helene struggles to manage a compromising situation.

Andrei's father is against him marrying Natasha. When the suggestion of a long engagement is made, Natasha is shocked and distracts herself at the country estate. She soon finds her love for Andrei tested. Rostova wants her son to marry into wealth and introduces him to a new candidate. Marya isn't impressed by her father's behaviour.

Pierre's life takes a surprising turn after fighting a duel. Natasha and Sonya both receive unexpected proposals. Nikolai makes a decision that has huge consequences for his family. Helene takes a new lover. Andrei shuts everyone out and feels depressed.

The French are kept at bay by the Russian's after a marginal success at Schongrabern. Andrei and Nikolai soon come to a shocking realisation. The tsar heads to Russia, confident he will be able to leads the troops, but Kutuzov is convinced that Napoleon is setting a trap. Natasha and her family are desperately waiting for news. Prince Vasily decides to marry off his son.

Everyone is rattled in Russian aristocratic society when Napoleon Bonaparte's French army invades Austria, drawing Russia into a conflict. Everyone that is but hot-headed Pierre Bezukhov, who is a fan of the French's politics. Pierre's close friend Prince Andrei is excited for the conflict, as he thinks he may of found his purpose in life, fighting on the front line. Natasha, a beautiful, lively young woman is desperate to experience more of what the world has to offer, finds herself romantically inspired by her brother and his new beau.