Okonkwo is a respected man among the Igbo people, but he lives in constant fear of becoming like his lazy, cowardly, shameful father. Out of fear of being like his dad, Okonkwo commits his first big sin by killing his adopted son, Ikemefuna. This alienates him from his eldest son Nwoye, to whom Ikemefuna was a like a brother. Okonkwo commits his second big sin by accidentally killing a clansman. This crime requires that he exonerate himself by spending seven years in exile in his motherland.
In his motherland, a village called Mbanta, Okonkwo’s feels despair and spends his time plotting his triumphant return to Umuofia. While in exile, Okonkwo also hears news of white men arriving in Igbo territory. The rumors become reality when missionaries show up in Mbanta and start causing trouble by converting villagers. Even Okonkwo’s oldest son becomes a Christian, and in rage over the betrayal, Okonkwo disowns his son.
After completing his seven-year exile, Okonkwo returns to Umuofia, but his reception is not as grand as he had hoped. This is because the missionaries have arrived and have changed the Igbo lifestyle, turning brothers against brothers, and enforcing a corrupt government and system of justice. Grieved and angered by the changes he sees the white men making, Okonkwo encourages the leaders of Umuofia to take aggressive action against the missionaries. Okonkwo and other community leaders burn the church down, but are later jailed and humiliated by the white men. Okonkwo, now eager for full-out war, murders one of the white government officials. When he realizes that the Umuofia will never rebel against their oppressors, Okonkwo commits suicide.