In the early stages of the invasion, Bolkonsky grapples with his disillusionment with the military life and his growing sense of detachment from the political affairs of Russia. He despises the rampant corruption and incompetence he sees among his fellow officers, and he begins to question the legitimacy of the war itself.
Meanwhile, Pierre becomes increasingly swept up in the patriotic fervor that has gripped Moscow in the face of the French threat. He initially plans to observe the battle from a safe distance, but he is moved by the heroism of the Russian soldiers and eventually joins a battery of artillery.
The Battle of Borodino, one of the bloodiest of the entire Napoleonic Wars, is depicted in harrowing detail. The Russian army, outnumbered and outgunned, suffers heavy losses but manages to hold the French forces at bay for an entire day. Bolkonsky's unit remains in reserve for much of the battle, but when they are finally called into action, he is struck by a shell that shatters his leg.
The aftermath of the battle is portrayed as a disaster for both sides. The Russian army is forced to retreat, and Moscow is left vulnerable to French attack. Anatol, who has been wounded in the fighting, is taken prisoner by the French and is revealed to have been involved in a scandalous affair with Helene Bezukhov, who has since died of illness.
The film ends on a bleak note, with Moscow in flames and Pierre wandering the streets in a state of shock and despair. The future of Russia and the fate of its people seem uncertain, and the once-great empire appears to be teetering on the brink of collapse.