This epic story intertwines the lives of several prominent Russian families over the course of eight years, during which Napoleon Bonaparte conquers much of Europe and seeks to invade Russia. The story opens in St. Petersburg, in 1805, at a party hosted by a rich socialite. She discusses the French threat with her friend, Prince Kuragin. She also praises his daughter, the beautiful Helene, but admonishes his son, Anatole, as a cad.
The prince asks her to introduce Anatole to Mary Bolkonskaya, the only daughter of Prince Bolkonski, a wealthy, retired military commander. Pierre Bezukhov, the illegitimate son of a wealthy count, arrives fresh from travels abroad. He is a large, simple man, who is not comfortable interacting with the aristocracy. Pierre is intrigued by Andrew Bolkonski, Mary’s brother, an officer in the military. They begin a tentative friendship founded on their discussions of philosophy. Much to Prince Kuragin’s dismay, his hopes of inheriting Count Bezukhov’s vast fortune are dashed when the count dies and leaves his wealth to Pierre.
In Moscow, the Rostov family host a feast day celebration in honor of their matriarch and her daughter, both named after St. Natalia. Natasha Rostov, 13 years old, spies on her brother and her cousin, Nicholas and Sonya, as they declare their love for each other and promise to one day marry.
Outside of Moscow, in the remote estate named Bald Hill, Mary Bolkonskaya sits under the tutelage of her exacting and dominating father, Prince Bolkonski. She is happy when her brother Andrew arrives with his pregnant wife, Lise. Andrew and their father argue over Napoleon’s genius, but the prince still sends his son off to war with a letter of recommendation to General Kutuzov, hoping to get his son a better position in the army.
Nicholas, Andrew and Anatole all set off to fight with the Austrians against Napoleon. Each has his own experiences in the war. Andrew is severely wounded and presumed dead by his family. Meanwhile, Pierre tries to fit in with Russian nobility, but Prince Kuragin’s daughter, Helene, who desires marriage to him to obtain his wealth, easily manipulates him.
Pierre weds her, but she soon hurts him by having an affair with a man named Dolokhov. Pierre challenges him to a duel in which he severely wounds Dolokhov. Fearing he has killed him, Pierre flees to the country. Discontent with life, he falls into the cult of Freemasonry. His innocent nature is preyed upon by those who serve him as he tries to be generous to his serfs. Throughout the story he searches for ways to help others and lead a good life.
After successfully marrying his daughter to Pierre, Prince Kuragin sets out to match his son, Anatole, to Prince Bolinski’s daughter. Although Mary is drawn to Anatole, she is too devoted to her widowed father to leave his side. She accepts her fate to remain a spinster as an act of Christian service. To the family’s relief, Andrew returns to Bald Hill. Unfortunately, his wife dies in childbirth. Andrew falls into depression. He leaves Bald Hill to run a smaller estate while Mary raises his son.
Nicholas returns home with his friend Dolokhov so that the two can convalesce after experiencing battle. Dolokhov is attracted to Nicholas’ cousin, Sonya. She rebuffs his advances, believing him to be a bad man. Nicholas encourages her to let go of their childhood promise to marry in order that she might accept Dolokhov’s proposal. She insists she will only love Nicholas. Later, in an act of revenge for her refusal, Dolokhov convinces his friend to gamble with him at cards and wins all Nicholas’ money, forcing Count Rostov to raise the cash to pay his son’s debts. Nicholas returns to fight the war.
Pierre visits his friend Andrew, and the two discuss their differing philosophies. Pierre believes in the pursuit of higher spirituality and doing good, while Andrew is convinced that life is too fleeting and desolate to chance caring deeply about anything. Pierre eventually lights a small flicker of hope within Andrew.
Andrew is further inspired when he visits the Rostovs at their country estate and sees the beautiful Natasha. Andrew is surprised at the new life within him and proceeds to St. Petersburg where he begins work within the tsar’s government. The Rostovs also come to St. Petersburg, and Pierre encourages Andrew to seek a relationship with the now 16-year-old Natasha.
Both men are smitten with the young woman, but as Pierre is still married, he cannot act on his feelings. Andrew asks for Natasha’s hand. His father does not like the match and insists that they wait a year before making the betrothal official. They agree, and Andrew sets off to travel the world, allowing Natasha to look elsewhere if she does not think marriage to an older man will make her happy. Andrew’s father takes out his anger at their betrothal on his daughter, Mary. She continues to suffer his emotional abuse with Christian grace.
Nicholas’ parents implore him to return from the army as the family is nearing financial ruin. His mother wants him to marry a rich socialite, thereby assuring the family can pay his debts, but Nicholas desires to marry for love. As he, his sister Natasha and their cousin Sonya enjoy participating in a masque at a neighbor’s estate, Nicholas realizes he truly loves Sonya. He kisses her and promises to marry her.
Natasha receives a letter from Andrew stating he must stay away longer due to his poor health. Although still in love, the young Natasha grows bored waiting. The Rostovs return to Moscow to arrange for the sale of their country estate and to order Natasha’s wedding trousseau. She visits her future in-laws, who have also returned to the city. The meeting does not go well, and Natasha is disheartened, believing her marriage may never take place. While attending an opera, she meets Anatole Kuragin, who is entranced by her. He pursues her romantically, even though he is secretly married to another woman.
Natasha is enamored of the dashing Anatole, and her feelings for Andrew become muddled. Anatole writes her a love letter, begging her to run away with him. Sonya finds the letter and the plot is stopped, but Andrew, upon hearing of her betrayal, nulls their betrothal. Natasha poisons herself with arsenic, but is given the remedy in time. She falls into depression until Pierre draws her out again. Andrew and Nicholas return to the army as Napoleon makes plans to march into Russia.
Natasha begins to make a recovery after a neighbor offers to take her to several religious ceremonies. The young girl accepts God’s grace and forgiveness for her actions. Pierre continues to visit the family and enjoy her company. Using a Masonic code, he predicts that Napoleon will be defeated in 1812. He sets off to the front to do what he can to stop the French. The Rostovs’ youngest son, Petya, receives special permission to join the army as well.
Andrew writes to his family, urging them to flee Bald Hill and return to Moscow as the French are rapidly approaching. His father initially ignores the advice, but then retreats to Andrew’s country estate. The Prince suffers a stroke and dies before they can continue to Moscow.
The French are nearly upon them, but the servants will not help Mary escape. Nicholas Rostov happens upon the estate and immediately sets the servants to work to help Mary. The two feel the spark of love, but do not act upon it before Mary sets off for Moscow.
Pierre meets up with the army at Borodino. Although significantly outnumbered by the French, the Russian army puts up a brave fight. The battle is considered a pivotal turning point in which Napoleon, who actually won, loses the battle because of low morale. Pierre comes upon Dolokhov, who begs forgiveness for his affair with Helene.
Meanwhile, Prince Andrew is again disheartened with life and reminisces about his father and Natasha. He is injured during the battle and, while awaiting surgery in the army hospital, witnesses his rival, Anatole Kuragin, having his leg amputated. Anatole dies from his injuries.
The decimated Russian army is forced to retreat and allow the French to take Moscow. Many nobles flee the city, even though the government asks them to stay. Disillusioned by the news that his wife seeks a divorce and from the battle he witnessed, Pierre flees in secret to Moscow. Nicholas writes to his family, who are preparing to leave Moscow, to inform them that he has formed an attachment to Mary Bolkonskaya. The family is thrilled as the marriage would alleviate their debt.
Sonya still hopes to wed Nicholas. The Rostovs open their home to wounded soldiers. The count also removes his personal belongings from carts so they can be used to help move the injured. Prince Andrew is among the dying brought to the house, but the countess hides the truth from Natasha.
Napoleon is insulted to learn that the elders of Moscow have fled rather than remain and welcome him as victor. The one Russian official left is angered that he has not been called on to organize a battle. In a huff, he orders that prisoners and lunatics should be released. As a mob of peasants gathers outside his home, he brings out a political prisoner and orders the crowd to kill him. As they beat the prisoner and another man, the official gets into his carriage to escape the city. The French soldiers, enjoying the freedom the empty city affords, accidentally cause fires that rage throughout Moscow.
Pierre becomes obsessed with the thought of assassinating Napoleon. Although sidetracked by a French officer whose life he saved, Pierre finally ventures out to complete the deed. He is arrested by the French under suspicion of being a spy. He is humiliated in jail and brought out to be executed, but he is saved at the last moment and returned to prison. Pierre forms a friendship with another prisoner and comes to learn that through faith, happiness can be found in simple things, like food, warmth and the absence of pain.
Meanwhile, Sonya tells Natasha that Andrew is among the wounded. Natasha sneaks out to him when her family is asleep. She begs Andrew to forgive her. Princess Mary and Nicholas are brought together again by her aunt. He is confused by his feelings for Mary as he still loves Sonya. Under duress from her aunt, Sonya writes him a letter freeing him from their betrothal. Mary visits the Rostovs in order to tend to her brother. She and Natasha are by his side when he dies. The Rostovs also grieve the death of their youngest son, Petya, who was killed by the French.
The Russian army returns to Moscow, and Napoleon, rather than engaging in battle, retreats. The Russians begin a series of guerilla attacks on the retreating troops. Pierre, who has been forced to march as a prisoner of war, is rescued. He returns to Moscow a free man. Now a widow, Pierre has found contentment through his trials. He visits Princess Mary and is surprised to see Natasha. The two women have bonded over the loss of Prince Andrew.
Pierre knows he loves Natasha, and Mary assures him that, if he gives Natasha time, she will agree to marry him. In the epilogue, the reader learns that Natasha and Pierre marry and live rather ordinary lives, outside the circle of high society. Nicholas and Mary also wed, which allows him to pay off his family’s enormous debts.