The missionaries ask for a plot of land on which to build their church, and Uchendu gives them a plot in Mbanta's Evil Forest. The next morning, the missionaries begin clearing the forest in order to build a church, and the inhabitants of Mbanta expect them all to be dead within four days. When none of them die, they win their first three converts.
The missionaries' actions begin to challenge the clan's beliefs—by building a church in the forest and not dying they show either that the forest isn't actually dangerous or that their own god is stronger than the forces of the forest, which is likely why the first three people converted.
Nwoye keeps his attraction to the new faith a secret, not wishing to anger his father, but he strays near the church and listens to the singing on Sundays.
The music draws Nwoye to the church on Sundays, but he knows that his father, who approves of tradition and masculinity, would disapprove.
The Mbanta assume that their gods and ancestors will punish the white men in twenty-eight days, since their gods are sometimes long-suffering, but never permit a man to defy them longer than that. However, when the day comes that all the missionaries should die, they're all still alive, winning them a handful more converts. Among them is a woman named Nneka, who has had four previous sets of twins, all of which had immediately been thrown away after being born.
The church wins the most converts when it seems more powerful than the clan's religion. In addition, the new religion attracts those who have suffered under the old religion, such as Nneka. Those who have been caused grief by the old traditions want change.
One morning, Okonkwo's cousin, Amikwu, passes by the church and sees Nwoye among the Christians. He tells Okonkwo what he's seen, and when Nwoye returns to the compound, Okonkwo attacks him, gripping him by the neck and demanding to know where he's been. Uchendu stops Okonkwo, who lets go of Nwoye, and Nwoye walks out and never returns. He decides to join the Christians in Umuofia.
Nwoye seems to be attracted to the Christians because they offer a less violent option (of course, as we'll see, they can be pretty violent too). Okonkwo's physically violent reaction to seeing Nwoye among the Christians is therefore exactly the wrong thing—in trying to force Nwoye to stay, he in fact pushes him away. Nwoye, like others who feel mistreated by the old traditions, naturally move toward the new option. They represent the change within the clan.
Okonkwo sits in his hut, wondering how he could have been cursed with such a son. He thinks of his own nickname as the “Roaring Flame,” and wonders how he could have borne a weak son like Nwoye. Then, as he gazes into the fire, he realizes that “living fire begets cold, impotent ash.”
This is the first instance we see Okonkwo employ a metaphor, since he's usually straightforward and blunt. He believes that his strength fostered feminine qualities in Nwoye. He doesn't see that this same aggression will eventually burn him out as well, since fire eventually consumes its source.