Tolstoy reiterates his belief that history is determined by infinite minute decisions made by average people.
The Russians are unable to mount another attack against the French. They retreat from Borodino to the town of Fili.
Kutuzov, Count Bennigsen, and several other generals discuss strategy. Kutuzov and Bennigsen continue to wrestle for power. Eventually, Kutuzov decides to disregard the other officers’ advice and proceed using his own judgment.
The generals hold a council at a peasant’s house and argue about whether they should retreat and surrender Moscow, or have another battle. Kutuzov orders a retreat, and then reflects to himself about how long before the necessity of abandoning Moscow was assured.
The nobility begins to evacuate Moscow. Count Rastopchin, who is in charge of the city in the tsar's absence, tries to discourage flight.
Meanwhile in Petersburg, Hélène Bezukhov has a problem. For the first time, two of her lovers are in the same city and on the verge of finding out about each other. She proposes marriage to both of the lovers, then converts to Catholicism in hopes of getting her marriage to Pierre annulled.
Rumors spread that Hélène is entertaining two marriage proposals, and no one in society questions the fact that she already has a husband – except for her jealous mother and the always-frank Marya Dmitrievna Akhrosimov. Hélène decides to marry the elder of the two suitors.
Pierre, out of sorts after the battle, wanders on a road alone towards Knyazkovo. Some foot soldiers give Pierre some food and escort him back to an inn, where he must sleep in the carriage because there are no rooms.
While lying in the carriage, Pierre convinces himself that he would be a better person if he were poor and common like the soldiers who helped him. The next day, as he prepares to follow the retreating Russian army, he hears that Anatole Kuragin and Prince Andrei have died.
When he arrives in Moscow, Pierre hears rumors that the city will be surrendered – and, on a more personal note, that there is unspecified trouble with his wife.
Count Rastopchin summons Pierre and questions him about his associations with a few Freemasons who have been accused of treason. Pierre mildly asks if the men have actually broken any rules. Count Rastopchin warns him to flee Moscow before the French arrive, so he does.
The Rostovs wait until the last minute to evacuate Moscow, even as the city is bustling with news and reports.
We learn that Pyotr Rostov, now sixteen, is enjoying army life, but his mother is distraught at the thought that her youngest child might be killed. She arranges for Pyotr to transfer to Pierre Bezukhov’s regiment (the one he is organizing), which is far from the fighting. However, Pyotr comes home on leave just as the French are about to invade the city. Sonya has heard about Nikolai Rostov’s encounter with Marya and feels bitter and jealous.
Natasha volunteers the Rostov house as an infirmary for wounded officers. Meanwhile, Countess Rostov continues to plot ways to keep Pyotr out of danger.
Natasha and Sonya help pack the Rostovs’ furniture. Meanwhile, one of the wounded officers brought to recover at the house is Prince Andrei Bolkonsky. The woman who brings him in does her best to prevent Natasha from seeing.
Count Rostov absent-mindedly agrees that the family’s carts can be used to transport wounded soldiers, instead of for their own possessions. When Countess Rostov realizes that this means they will have to leave most of their things behind, she is mortified.
Lieutenant Berg visits the Rostovs. They are overwhelmed by the stressful situation, and Natasha convinces them to volunteer all their carts to transport the wounded – which means they must leave all of their possessions behind.
Sonya and Countess Rostov learn that Prince Andrei is among the wounded who they are transporting. They try to conceal this fact from Natasha. As they ride out of town, Natasha notices Pierre sneaking back into Moscow in disguise, a sighting that brings her great pleasure. They stop him, and Natasha talks with him, asking her parents if she can stay with Pierre. After brief conversation, they part.
Pierre goes to the house of Osip Bazdeev, his Freemason mentor from Volume II. He has promised to save some of Bazdeev’s books. When he gets there, he asks a servant to find him some peasant clothes and a pistol.
Napoleon prepares to invade Moscow as the Russian army retreats.
Meanwhile, Moscow is almost entirely empty.
Russian troops try to escort the last of the wounded soldiers out of the city, but a crowd of panicked civilians has blocked the bridge. The army eventually clears the crowd by pretending it will soon fire on them.
A few servants remain at the Rostov estate. When a young officer claiming to be a relative comes and asks for money, the housekeeper gives him 25 roubles.
A number of working people are still left in the city. Some of them drunkenly rebel against a landlord, while others chase a police officer. They become desperate when they realize the French will take the city.
Count Rastopchin is so concerned with preventing an insurrection that he lies to the lower classes about Moscow having been surrendered and does little to keep them safe. He calls for Vereshchagin, one of the Freemason political prisoners, to be brought to him.
An angry crowd gathers outside Rastopchin’s office. He is frustrated that he cannot control them. He presents Vereshchagin to the crowd as a traitor and allows them to lynch him. As he flees the city, Rastopchin encounters a madman who thinks he is Jesus.
The French enter Moscow and the soldiers begin to loot the city. Within the next few days, the city burns to the ground. Each side claims the other one set the fire, but Tolstoy argues that it was accidental.
Pierre decides to try and assassinate Napoleon, believing this will give him an opportunity for heroic martyrdom. His desire is described as a "madness" (898).
Some French officers enter the Bazdeev house. As part of his assassination plot, Pierre pretends not to speak French, but he forgets this façade when Makar Alexeevich (Osip Bazdeev’s mentally disabled brother-in-law) tries to shoot an officer with a stolen pistol. The French officer, Captain Ramballe, jocularly thanks Pierre and decides he must be a Frenchman. At Pierre’s request, Ramballe pardons Makar.
Ramballe invites Pierre to dinner. They get drunk on French wine and have a merry discussion, which Pierre feels guilty about enjoying. He confides in Ramballe about his love for Natasha. At the end of the evening, Pierre sees a small fire in the distance and stumbles home.
The Rostovs sadly watch Moscow burn from afar as they flee the area.
Sonya lets slip to Natasha that Prince Andrei is with the family and is wounded. Natasha, distraught and certain the reunion will be painful, decides to visit him. When he sees her, he holds out his hand.
After being wounded, Prince Andrei has found a new sense of spiritual purpose and has renewed his capacity for forgiveness and compassion. When Natasha visits him, he forgives her for her past indiscretions. She faithfully nurses him from that day on.
On his way to try and kill Napoleon, Pierre sees a woman panicking because her daughter is lost. Pierre diverts from his mission and rescues the daughter from a burning house.
Pierre cannot find the girl’s mother, so he hands the girl over to a woman who claims to know the family. He sees a French soldier trying to rape a young woman, and attacks the soldier. Some French officers see the beating and arrest Pierre.
The destruction of Moscow may seem like an inhumane event – one of the great sites of human culture is surrendered to fire and pillaging. However, this unlikely event forms a backdrop for Tolstoy’s exploration of how people come to do good things. This theme first comes up as the Rostovs prepare to evacuate Moscow and (somewhat accidentally) volunteer their carts as medical transports. This proves to be a significant act of charity; while the other noble families have fled the city weeks ago, the Rostovs have stayed and are now transporting nearly 100 wounded officers. However, their altruism doesn’t come from any generous feeling. Natasha impulsively volunteers the carts when she gets bored packing her clothes, and the weak-willed Count Rostov feels obliged to follow through on his daughter’s offer.
The Rostovs’ ambiguous generosity is consistent with the way they were portrayed earlier in the novel. Count Rostov maintains his gentle and resigned demeanor, and the scene in which he allows all the family’s carts to be given to the military echoes the one when he takes responsibility for Nikolai’s gambling debts to Dolokhov. Both incidents have they same result: they further strain the Rostovs’ already precarious finances, but are a result of the family's gentleness.
Pierre’s acts of generosity are similarly ambiguous. When the French first invade Moscow, he believes that he can best help humanity through assassinating Napoleon and getting himself killed in retaliation. If the violence of Pierre’s ambitions isn’t questionable enough, he seems entirely fixated on the idea of heroic ‘suicide by cop.’ He doesn’t seem to care if he succeeds in killing the emperor, as shown when he chooses to use a dagger instead of a pistol despite his doubts about whether it will get the job done. Ironically, scenes of violence are what rouse Pierre from his fantasies of bloody heroism. The sight of a hysterical woman and a burning house inspire him to rescue the little girl, after which he decides that it’s better to help the people around him than to try to kill the emperor. He is even more inspired when he sees a French soldier about to rape a young woman.
Unlike the Rostovs, whose self-sacrifice is mostly accidental, Pierre’s generosity is intentional. However, he is only able to help those around him because he matures quickly. He starts out indulging his childish fantasies of heroism, but when he sees the horrifying reality of violence, he gallantly throws himself into the fray in order to help others – and in doing so, ceases to think about himself in romantic or heroic terms. This narrative parallels the experiences that Prince Andrei and Nikolai Rostov have when they go to battle for the first time.
And indeed, Pierre's decision to help others rather than pursue his idealized heroism reveals his maturity in terms of the conflict between spiritual and material existence. Before, when confronted with the petty, material world of society, Pierre has been pushed to disappear into his spirituality. Here, he chooses to act in the opposite way; he has a spiritual goal, but when confronted directly with suffering in the world around him, he chooses to engage the world and thereby reveals the true depths of his morality.
At the end of the chapter, Tolstoy includes a small coda to his exploration of how individuals become heroes. When Pierre rescues the girl from the burning house, a French soldier helps him find her. “Faut être humain” (928), he explains – that is, ‘one must be human.’ This comment suggests that regardless of what inspires people to commit heroic acts, compassion is a universal human quality. And by default, patriotism is potentially a ruse behind which true humanity ebbs and flows.
Finally, one should consider how interesting Tolstoy's depiction of Moscow's desertion would be to his contemporary reader, for whom the event was not so far removed historically. Rastpochin, a real historical figure who might have been responsible for ordering the city burnt to the ground, is one who would have inspired strong responses from a reading audience, and his villainy here is clear. Watching the nobility flee the city in such droves, even as some of them pretend to maintain the same air of civility, makes this the point in the novel when 'war' and 'peace' have most coincided. There will be no more detached political discussions at parties, but instead, everyone is being touched by war, a fact that Tolstoy might argue was always the case whether the people involved knew it or not.