The novel takes place in Nigeria prior to and during the Nigerian Civil War (1967–70). The effect of the war is shown through the relationships of five people's lives including the twin daughters of an influential businessman, a professor, a British expat, and a Nigerian houseboy. After Biafra's declaration of secession, the lives of the main characters drastically change and are torn apart by the brutality of the civil war and decisions in their personal lives.
The book jumps between events that took place during the early and late 1960s, when the war took place, and extends until the end of the war. In the early 1960s, the main characters are introduced: Ugwu, a 13-year-old village boy who moves in with Odenigbo, to work as his houseboy. Odenigbo frequently entertains intellectuals to discuss the political turmoil in Nigeria. Life changes for Ugwu when Odenigbo's girlfriend, Olanna, moves in with them. Ugwu forms a strong bond with both of them, and is a very loyal houseboy. Olanna has a twin sister, Kainene, a woman with a dry sense of humor, tired by the pompous company she runs for her father. Her lover Richard is an English writer who goes to Nigeria to explore Igbo-Ukwu art.
Jumping four years ahead, trouble is brewing between the Hausa and the Igbo people and hundreds of people die in massacres, including Olanna's beloved auntie and uncle. A new republic, called Biafra, is created by the Igbo. As a result of the conflict, Olanna, Odenigbo, their young daughter, whom they refer to only as "Baby", and Ugwu are forced to flee Nsukka, which is the university town and the major intellectual hub of the new nation. They finally end up in the refugee town of Umuahia, where they suffer and struggle due to food shortages, the constant air raids and the environment of paranoia. There are also allusions to a conflict between Olanna and Kainene, Richard and Kainene and between Olanna and Odenigbo.
When the novel jumps back to the early 1960s, we learn that Odenigbo has slept with a village girl, Amala, who then has his baby. Olanna is furious at his betrayal, and sleeps with Richard in a moment of liberation. She goes back to Odenigbo and when they later learn that Amala refused to keep her newborn daughter, Olanna decides that they would keep her.
During the war, Olanna, Odenigbo, Baby, and Ugwu live with Kainene and Richard, where Kainene was running a refugee camp. Their situation is hopeless, as they have no food nor medicine. Kainene decides to trade across enemy lines, but does not return, even after the end of the war a few weeks later. The book ends ambiguously, with the reader not knowing if Kainene lives.
