This is where we start: the Underground Man isn't anything, and he can't ever become anything. Talk about static and unchanging.
The conflict becomes clear once the Underground Man starts talking about "the wall," his metaphor for the laws of nature. (Read all about it in "Symbols, Imagery, and Allegory.") Consider these two images: the man of action is a bull who is stopped cold by the stone wall. The man of consciousness can't do anything about the wall either, but he is willing to smash his head against it. Both of these suggest that the real conflict is the stone wall. As the Underground Man continues his discussion, the wall becomes almost an antagonist. The laws of nature, after all, are what threaten man's free will.
On the other hand, you could argue that the conflict is more about inertia and consciousness than anything else. In this way, the conflict is like a further exploration of the initial situation. "You can't act? OK, why?" The answer is hyper-consciousness, which leads to inertia. In this case, consciousness is the real conflict here. After all, the Underground Man himself claims that "consciousness is an illness." (Of course, he later negates this sentiment, but that's part of the complication stage).
As you see below, the climax, denouement, and conclusion of Notes from the Underground all fall in the last chapter of Part II. This means that the majority of Notes comprises the complication. Here's one example: the Underground Man states during the conflict stage that consciousness is an illness. He goes on to say that man "prizes it and would not give it up for any satisfaction." Here's another one: the Underground Man claims to not have readers at all – that certainly complicated the process of us reading his work. And that's just Part I. Part II is chock-full of complication after complication, which you might expect when a man like our narrator is interacting with normal people in the real world.
It would be reasonable to think that Liza slamming the door in Chapter Ten is the climax. You can argue that if you want to, but we wanted to offer an alternative.
Consider the idea that the scene in which the Underground Man says "They won't let me…I can't be good!" is actually the climax of the story. You'll want to pay particular attention to the word "good" and then go on back to the very first sentence of the novel: "I am a sick man…I am a spiteful man. I am an unattractive man." As translator Michael Katz points out, the Russian word for "spiteful" can also be read as "evil." The two words – dobryi in the novel's opener and zloi in this line form a pair of opposites, much like our good/evil pairing.
Now, this does quite a few nifty things. Structurally, it packages Notes in between these two book ends. Thematically, it forms a great start/end dichotomy. 1) I am evil, and 2) They won't let me be good. This has some big implications for the Underground Man, who is all about free will and personal agency. He refuses to abide by 2+2=4, because if he wants 2+2=5, that's what he's going to believe. But that's a far cry from the defeatist attitude we see here. It's as if the "I'm going to smash my head against the wall" Underground Man were admitting that, actually, his free will is out to lunch and won't be back any time soon. It's not that his consciousness is causing inertia –which he claimed for most of the novel – it's that "they" won't let him move from his spite.
To peg this moment as the climax is to take a somewhat extremist view: if this moment of defeat is the climax of the Underground Man's argument, things aren't looking too hopeful for our narrator. It also raises a lot of difficult questions, chief among them: Who are the "they" to whom the Underground Man refers?
No matter which moment you identity as the climax – the door slamming or the Underground Man's vocal finale, the suspense stage is largely the same: will the Underground Man lose Liza? If you go with Option #1 (the door slamming) climax, then the suspense lasts about four lines while the Underground Man runs after her in the street. If you choose Option #2, then the suspense starts earlier, from their second and final (and short-lived) time in bed. Either way, you're basically talking about the same dilemma over losing Liza.
At this point, it's clear that Liza is gone and the Underground Man will be left alone, forever. (Of course, we already knew that, as he's forty now and living alone underground, but it doesn't mean the story doesn't have its element of suspense. After all, we always knew Indiana Jones was going to live, but that didn't make watching Harrison Ford any less entertaining.) Usually, the denouement makes something clear for the reader – all the Underground Man has done is raise more questions. This is fitting, since we shouldn't really expect to walk away from a work about uncertainty with any degree of confidence in objective truth.
The conclusion begins right when the Underground Man pulls out of his narrative and says, "…perhaps I should end these Notes here?" Then he takes a step back and is able to address what he's just written as a whole. You know how some English teachers talk about how a stellar conclusion does more than just reiterate, how it opens the work in new and interesting ways without leaving loose ends, how it encourages the reader to take the arguments further himself? Well this is pretty much textbook-perfect as far as stellar conclusions are concerned.
So what does he say, exactly? To start, he forces us to digest Notes in a very personal way. Until now, we might have gotten away with putting a wall between us and the Underground Man. He's doing his weird underground things in his little hovel, which seem to have nothing to do with us. But the conclusion strips away that barrier. "I have only in my life carried to an extreme what you have not dared to carry halfway," the Underground man declares. Now, like it or not, we have to compare ourselves to this guy.