The novel opens on the 20th of May in the year 1859 with Nikolai waiting on his front porch for the arrival of his son Arkady.
The narrator tells us that Nikolai is the son of a Russian general. He was the weaker of the two brothers and, while Pavel went on to become a captain, he hurt himself before he could enlist.
He fell in love with the daughter of a former landlord and had Arkady, but ten years later she died, which nearly killed him.
He thought of traveling abroad, but then the 1848 revolutions broke out, and he had to return home to manage his estate.
This is the first time Arkady has gone off to Petersburg without him acting as a chaperon.
Nikolai's thoughts are broken off by the arrival of his son. He is ecstatic to see him.
Arkady introduces Nikolai to his friend Bazarov, and tells him that Bazarov is brilliant and very important to him.
In the carriage on the way back, it comes out that Nikolai is having a relationship with a servant girl, Fenichka. He is very embarrassed about it, but Arkady hugs him and tells him it's no big deal.
Nikolai also tells Arkady what a tough time he's having with the peasants. Ever since he's freed them, they refuse to pay their taxes and many have become lazy.
Nikolai is chatty all night, and he has to stay up late because he is so excited by his son's arrival.
The next day at breakfast, Nikolai continues to be awkward and embarrassed about Fenichka. Arkady insists on going inside and introducing himself to her. Inside, Arkady finds that he has a new baby brother, Mitya. Nikolai is embarrassed yet again.
When he returns, they begin discussing Bazarov with Pavel. Arkady reveals to them that Bazarov is a nihilist. Nikolai doesn't know exactly what it is, but Arkady explains it.
Both Nikolai and Pavel are skeptical, though Pavel is more openly so than his brother.
When Bazarov returns, an argument breaks out with Pavel. Nikolai remains in the background, and does his best to mediate.
When Arkady tells Bazarov Pavel's story, we learn that Nikolai took his brother in at Maryino after he ruined himself chasing after a woman who turned out to be mad.
Pavel would never tell his brother, but he considers him impractical. Nikolai, by contrast, worships Pavel and admires his common sense.
The next day, Nikolai comes in to see Fenichka and is surprised to find that Pavel came in to play with Mitya.
We learn that Nikolai initially hired Fenichka's mother, Arina Savishna, and that after she died, he took her into the house. One thing led to another, and now they have a child together.
When Bazarov and Arkady are out walking, Bazarov hears Nikolai playing the cello. He laughs at an old man having such a silly hobby, but Arkady does not even smile.
After a few weeks, Nikolai overhears Arkady trying to defend him to Bazarov. He becomes melancholy, and, after Arkady gives him a book by a German philosopher (Bazarov's suggestion) that he doesn't understand, he worries about the gulf opening up between him and his son.
Another large argument breaks out between Pavel and Bazarov, this one much bigger than the first. Again, Nikolai tries to mediate, but with little success.
After the argument, he talks with Pavel and remembers a time when he told their mother, "Of course, you cannot understand me: we belong to two different generations" (10.121).
He thinks that the moment has now come where Arkady will say the same thing to him.
Soon after the outburst, Arkady and Bazarov leave to visit Nikolai's wealthy relative, Matvei Ilyich Kolyazin.
We don't see Nikolai again until the point when Arkady and Bazarov return after visiting the Odintsovs and then Bazarov's family.
When Nikolai finds a letter from Madame Odintsov's mother to Arkady's, Arkady uses it as a pretext to go visit Katya Sergeyevna.
Bazarov is left alone at Maryino, and, from time to time, Nikolai helps him out with his experiments.
Nikolai worries that his relationship with Fenichka is somewhat strained, that they are still held apart as master and servant.
When Pavel sees Bazarov flirting with Fenichka, he spies on them. Bazarov tries to kiss Fenichka, and the next day Pavel challenges him to a duel.
The duel ends with Pavel shot in the thigh and Bazarov treating him. They decide to conceal the cause of their fight from Nikolai, who is shocked.
Yet, after Bazarov leaves, Pavel asks his brother to do him a favor and marry Fenichka. Nikolai is thrilled, and tells Pavel the only reason he hasn't already is because he was worried that Pavel would disapprove.
The novel ends with the joint weddings of Arkady and Katya, and Nikolai and Fenichka.
When Pavel departs to live out the remainder of his life in Dresden, Nikolai tries to make a toast for his brother, but stumbles over his words.
Arkady and Nikolai now manage Maryino together, and Arkady has a young child that plays with Mitya.
Arkady deals with the estate itself, and Nikolai goes about and preaches to the peasants about the land reforms. Unfortunately, he is too mild to please either the peasants or the gentry.