Chaos takes hold as Napoleon marches into Moscow and the Rostovs rush to leave the city. As they hurry away, Natasha is astonished to learn the identity of one of her travelling companions and finds she at last has a chance to make amends. Sonya, meanwhile, comes under pressure from the countess to make a great sacrifice for her family.
Half-mad after his experience of battle, Pierre sets out to end Napoleon's onslaught once and for all, but is taken prisoner. As the harsh winter sets in, he witnesses horrors and acts of kindness that change his view of life forever.