Count Rostov has managed to hush up the scandal of the duel, and Nikolay, in the meantime, has become friends with Dolohov. In one of their talks, Dolohov states his intense nature: I would give my life to those I love, he says, and crush those who get in my way. For Dolohov, people are either useful or mischievous and almost all women are of the latter. He searches, he says, for a"heavenly creature, who would regenerate and purify and elevate me."
Dolohov falls in love with Sonya but she refuses to marry him even though Nikolay frees her of her promise to him. Sonya says she is content merely loving Nikolay and will demand nothing more from him. Meantime, Denisov, who is spending the Christmas holidays with the Rostovs, is captivated by Natasha.
Vengeful at Sonya's refusal, Dolohov plans a gambling party where he intends to fleece Nikolay of 43,000 rubles (the sum of his and Sonya's ages). Nikolay feels like a trapped mouse in the pitiless paws of a cat as he watches Dolohov's broad-boned hands deal out the fateful cards. His misery is more complete, since he had given his word of honor to his debt-ridden father not to ask for money.
In profound despair and shame, Nikolay enters the house where Sonya, Natasha, and Denisov are grouped around the clavichord. Denisov plays a song he composed for his"enchantress," and Natasha commences to sing it. Her pure untrained voice soothes Nikolay's spirit. As she hits a high note, his soul thrills and soars to a sphere beyond the world of Dolohovs, of losses, of honor."One might murder, steal, and yet be happy," Nikolay thinks in the ecstasy of the moment.
Confessing his shame to his father, Nikolay bursts into sobs as Count Rostov murmurs words of comfort, none of reproach, to his penitent son. Natasha, at the same moment, is in her mother's bedroom telling the countess that Denisov has made her an offer."Everyone is in love around here," remarks her mother, thinking Natasha is too young to consider marriage.
Crushed at Natasha's refusal, Denisov leaves Moscow the next day while Nikolay, having paid his debt to Dolohov, joins his regiment in Poland two weeks later.
The prevailing spirit in these chapters is intensity, and Tolstoy withholds his more characteristic tone of morality to emphasize this quality. The scenes of love and life-affirmation in the Rostov household not only complement the previous scene of death and birth at Bleak Hills but advance its spirit. Intensity, Tolstoy seems to say, is a quality equally important with moral awareness, for without intense feelings — be they negative or positive — one has no feeling of life. Dolohov's vengeful cat-and-mouse game with Nikolay is the way Tolstoy expresses the"law of intense life" which Dolohov maintains and which he states to Nikolay during their talks. Nikolay sums up this"law": One can be a criminal and be happy because the ability to feel and to be is more important than empty commitment to moral principles. Tolstoy's symbol of feeling and pure being is contained in Natasha's singing, therefore in Natasha herself. This is the quality that enchants Denisov. As the creature-embodiment of growth and naturalness, Natasha radiates love as naturally as she pours out her song. At this point, however, she is unready for a mature love affair.
"Intensity" is thus the keynote of the entire Book IV. Each main character — Pierre, Andrey, Natasha, Nikolay — has been brought to a state of fruition and definition and each has a unique destiny to be worked out in future events.