Pierre is sitting across from Dolokhov, Denisov, and Rostov, obviously distracted. He had recieved an anonymous letter and another tip-off that his wife and Dolokhov were having an affair, but he is unsure what action he'd like to take, if any. When he thinks about it, "something terrible and ugly rise[s] up in his soul."
He is having trouble believing it of Dolokhov and his wife, though he knows it could be true. His took Dolokhov in, clothed him, gave him money, while his wife complained of his presence. But he has seen the glee in his eyes when he does something cruel "'He must think everybody's afraid of him, it must make him feel good. He must think I'm also afraid of him. And, in fact, I am afraid of him,' thought Pierre, and at these thoughts, he felt something frightful and ugly rise up in his soul."
Pierre is so engrossed that he forgets to drink to the sovereign when Rostov toasts, which annoys Nikolai. Then Dolokhov toasts to the health of beautiful women and their lovers (which is really over-the-top). Then, a servant lays down music for the cantata for Kuzutov (that sounds like cuckoo for cocoa puffs), Dolokhov snatches it before Pierre can see it. Pierre demands it back, angrily, and Dolokhov won't give it. "Dolokhov looked at Pierre with his light, merry, cruel eyes, and that the same smile, as if to say: 'Ah, this is what I like.'" He challenges Dolokhov to a duel.
At that moment, he is sure of both Dolokhov and his wife's guilt. There is no turning back. Rostov will be Dolokhov's second, and Nesvitsky Pierre's.
Rostov and Dolokhov sit up late, where Dolokhov admits he's not nervous, that his only intentioned is to kill as quickly as possible.
The next morning they meet for a duel at eight. Pierre hasn't slept. He is sure of his wife's guilt, though, and feels no reason to preserve Dolokhov's honor. Nesvitsky tries to convince him to let it go, but he says it doesn't matter, and then asked how to fire the pistol, as he's never held one.
Nikolai doesn't convince Dolokhov to surrender, either, so they are to walk from forty paces to ten, in fog in which they can barely see, to possibly kill.
This chapter is great in suspense building. You just feel Pierre's blood boiling, and the thing in him that wants to get out over the kind of natural oafishness that he normally displays. He's not even wearing glasses in this chapter, which further intensifies his cluelessness. The writing is visceral, from his POV, following every turn of thought. And it's great the following morning as well, when he follows through even though he might not make it out alive. He feels lost, and must act.
From the maiden aunt voice, I'm actually glad of it. Helene was a bad match, forced on to him by Vassily, and perhaps with this people will see that he might have a spine when pushed and give him his due for something besides his money. I do like Pierre. I hope he wins.
6 months ago