The novel is the tragic story of Okonkwo, the protagonist, and the Igbo culture of Nigeria. We learn from the outset that Okonkwo is a respected leader among the Igbo community in Umuofia, in eastern Nigeria. Though he grew up under the perceived weakness of his father, he his determined from an early age to distinguish himself. He first gains notoriety after defeating Amalinze the Cat in a wrestling match. From this victory, he goes on to gain many titles and honors.
We learn that Okonkwo’s father was lazy and prodigal. Unoka, the father, frequently borrowed money which he squandered on drinking Palm wine and getting drunk with his friends. His foolish ways left his family and children hungry. Unoka was known in the community and was considered a failure. The name he gained was agbala, which means one who resembles a woman and has no money or property. He dies in squalor and shame, leaving nothing for his family.
Because of his idle and drunken ways, Okonkwo hates his father. He wants to be nothing like him, and resolves to live up to an ideal of being “manly.” Unfortunately, he seems to err in the opposite direction, being insensitive, controlling, and dominating to his wife and children.
As a leader in his community, he finds himself caring for a young boy named Ikemefuna who was given to the village as a peace offering by the neighboring Mbaino in order to avoid war with Umuofia. Ikemefuna becomes close to Okonkwo’s son, Nwoye and Unwoye becomes attached to the boy.
As the years pass, Okonkwo becomes increasingly harsh and brutal. At one point he flies into a rage and violates the Week of Peace when he beats his youngest wife, Ojiugo, after she went to braid her hair at a friend’s house rather than prepare the food for her children. In another incident, Okonkwo beats his second wife, Ekwefi, and shoots at her with a gun because she forgot some important ingredients for a festival called the Feast of the New Yam.
A crisis point arises during the coming of the locusts. Okonkwo is given a message from the elder of the village, Ogbuefi Ezeuder, that came from the Oracle. Okonkwo is instructed that Ikemefuna must be sacrificed in part to atone for the Umofian woman who had been killed three years earlier in Mbaino. However, Okonkwo is specifically instructed to not kill the boy himself. Okonkwo believes it would be a sign of weakness to not perform the ritual killing, and he kills Ikemefuna himself with a machete. As a result, Nwoye begins to pull away from his father and the other clansmen.
After the killing of Ikemefuna Okonkwo falls into a depression. His fiend, Obierika expresses his disapproval of things and explains to him that the killing will offend the Earth Goddess who will seek her revenge. After talking about things with his friend, Okonkwo is finally able to get some rest. He is awakened by his wife, Ekwefi who tells him that their daughter, Ezinma is dying and in need of help. Okonkwo goes to gather preparations to make medicine to help his daughter.
Later, a trial is held in the commons of the village. The counsel consists of nine clan leaders which includes Okonkwo. Each represents the spirit of their ancestors. The counsel is called the egwugwu, and they are assembled to hear a dispute between and estranged husband and wife. It seems that the husband beat his wife, Mgbafo, severely and she escaped him to her brother in her home village. Her husband demands that she be returned. The egwugwu instruct the husband to take wine to his in-laws and to beg his wife to come back. In spite of the severity of the case, the egwugwu wonder why such a trivial matter would be brought before them.
Meanwhile, the priestess Chielo visits Ekwefi, who is Okonkwo’s second wife, that Agbala the Oracle of the Hills and Caves must see Ezinma. Ekwefi and Okonkwo protest and try to refuse, but they cannot deny the Oracle. Chielo carries Ezinma on her back through the nine villages until she enters the cave of the Oracle. Ekwefi secretly follows, in spite of the warnings from Chielo to stay at home. As it turns out, Okonkwo meets her at the entrance to the cave. The following morning, Chielo takes Ezinma back to Ekwefi’s hut and puts her to bed.
Soon after this, Ogbuefi Exeudu dies. This worries Okonkwo because he defied Ezeudu in killing Ikemefuna. Ezeudu was one of the most honored people in the village, having achieved titles beyond most anyone else. During the funeral, Okonkwo’s gun accidentally fires and kills Ezeudu’s son. The accidental killing of a clansman is considred a crime against the Earth Goddess, and Okonkwo and his family are exiled form Umofia for seven years. After they leave, a group of men come and destroy their compound and kill all of Okonkwo’s animals in order to cleanse the village of Okonkwo’s crime. Obierika stores Okonkwo’s yams in his barn. He begins to worry about the loss of the old traditions of the Igbo people.
Okonkwo is taken in by his maternal uncle Uchendu who is a village elder. Okonkwo is given a plot of land to begin anew, but he is depressed. He starts to blame his personal spirit, or chi, for all of his failures.
In the second year of his exile, Okonkwo’s friend Obierka visits him and brings news of the village of Abame. He tells Okonkwo that a white man on a bicycle visited the village. The elders of Abame consulted the Oracle which explained that the white men would eventually destroy the entire village. In order to prevent this, the villagers killed the white man. As a result, a group of white men came and destroyed the entire village. Abame is now gone and deserted.
Okonkwo believes it was foolish to kill a man they knew nothing about. Obierika gives Okonkwo money made from selling his yams and his seed-yams and promises to continue doing this until Okonkwo and his family are able to return to Umofia.
Soon after this, six missionaries, including a white man, come to the village of Mabanta. The white man explains Christianity, which Okonkwo thinks is nonsense. However, his son Nwoye is captivated and is soon converted to Christianity.
The village gives the missionaries some land in an area they believe is the Evil forest with the belief that the missionaries will die of they build their church on this site. But when nothing bad happens to the missionaries, many people in the village of Mbanta conclude that the missionaries must have special powers and magic. The first converts are the efulefu, or weak and worthless men of the village. Soon others follow including a woman. The missionaries work compounds and they build a school in the village of Umofia. Nwoye goes to attend the school and soon after leaves his father to be educated by the Christian missionaries.
Eventually the time of Okonkwo’s exile is over. He prepared a feast to show gratitude for his family who helped him, and he returns to Umofia.
Upon his return, Okonkwo finds that the village of Umofia has been completely transformed by the white men. Many of the men of the village have converted to Christianity. The white men have built a prison to house people who break the white man’s laws. The white men have instituted a government of their own, and they have employed natives of the village to work for them. Okonkwo is astounded and cannot understand why the people of the village have not risen up violently against the white men and their oppressive church and government.
As it turns out, some of the Igbo clan are quite happy with the changes, and Mr. Brown, the white missionary, treats the Igbo traditions with some respect. He actually makes attempts to understand the traditions and customs of the culture. This allows him to be on good terms with many of the elders and clan leaders. His understanding allows him to encourage the Igbo people to get an education. Mar. Brown explains to Okonkwo that his son has changed his name from Nwoye to Isaac and is now away studying at a teaching college. In spite of all this, Okonkwo is disturbed and unhappy with all of the changes.
The peace of this situation is interrupted when Mr. Brown falls ill and is replaced by Reverend Smith. This white man is completely intolerant of Igbo traditions and institutes strict rules against them.
As a result of this, a zealous convert form within the Igbo reveals one of the egwugwu, an egredious violation of Igbo law and custom. In response, the egwugwu burn the compound that belongs to the offender and the Christian church in order to punish the missionaries.
A District Commissioner learns of these problems and returns to Umofia in order to meet with the elders, including Okonkwo. All of these men are put in jail until they can pay a fine of 250 cowries. The people of the village collect the money and pay the fine.
The next day a meeting is called of the clansmen. Several messengers from the new court arrive in order to prevent the meeting. It is at this point that Okonkwo steps forward and beheads the leader of this group. As the remaining men run for their lives, Okonkwo sees that no one is coming forward to pursue them. He realizes that the people will never stand up to the white men. Things have fallen apart. He finally hangs himself.