Adichie's book traces the events that shook Africa during the early and late 1960s, including the period when the Nigerian Civil War took place. In crafting her narration, Adichie takes a beautifully anachronistic approach, flowing back and forth in time to tell the tale of those affected by war. The first and third major portions of the book are devoted to the early 1960s, while the late 1960s are depicted in the second and fourth portions.
At the beginning of Part I, Ugwu, an Igbo boy, has to go to Nsukka as a houseboy for Odenigbo, a professor of mathematics. Odenigno has fallen in love with Olanna, the daughter of a wealthy Nigerian. She ends up moving in with Odenigbo. She also meets his academic friends, who gather to argue about politics on a regular basis. Encouraged by Odenigbo, Ugwu himself gets the opportunity to go to school.
In another core perspective of the story, an English expatriate and aspiring writer named Richard Churchill leaves his girlfriend Susan for Kainene, with whom he has fallen in love. Kainene is Olanna’s twin, though the two of them are not identical in appearance. Richard befriends Olanna and Odenigbo after moving to Nsukka. Soon, Olanna and Odenigbo start attempting to have a baby.
In Part II, two coups follow in fairly quick succession, destabilizing the Nigerian government. The second coup is accompanied by a massacre of Igbo civilians in the North. Olanna escapes from this now dangerous region with the help of Mohammed, a former love interest. Richard witnesses some of the violence while returning from abroad; during a stop in an airport, he watches as employees of Igbo descent are gunned down. Having seen traumatic instances of bloodshed herself, Olanna loses the ability to walk and begins to experience distressing episodes known as "dark swoops." She recovers, but Odenigbo and all the members of his household evacuate Nsukka as enemy forces approach.
Odenigbo, Olanna, Ugwu, and the family's young daughter, Baby, resettle in Odenigbo's hometown of Abba. They settle in with Odenibgo's mother, then evacuate to a new area, Umuahia. However, Odenibgo's mother refuses to leave her hometown. Ugwu is disappointed with the house in Umuahia, which lacks modern luxuries, but Olanna and Odenibgo try to make the best of their new life. They are formally married in this new community. Unfortunately, there is an air raid during the reception.
The story then returns to the period before the war in Part III. Olanna has gone to London, and Mama (Odenigbo's mother) comes to visit Odenigbo. She brings with her a girl named Amala, with whom Odenigbo sleeps. When Olanna finds out about the affair, she moves out. She then gets intoxicated one day and sleeps with Richard; while they decide not to tell Kainene, Olanna tells Odenigbo.
Eventually, Olanna and Odenigbo come together again and adopt Amala’s girl. This character, Baby, turns out to be the child mentioned in the earlier narrative. Kainene finds out about Richard's infidelity with Olanna but doesn’t leave him. Instead, she destroys one of his manuscripts.
As the story returns to the war-torn period in Part IV, starvation becomes an epidemic. Aid to Biafra is blocked by Nigeria and the conflict is more or less ignored by major foreign powers. Odenigbo’s mother dies and Odenigbo himself starts drinking. Ugwu is conscripted into the army and is wounded in a battle. Kainene takes in Olanna’s family after the fall of Umuahia to the Nigerians.
During an attempt to trade across enemy lines late in the war, Kainene disappears and is never found. After the war ends, Olanna and Odenigo go back to Nsukka, where they are horrified to find that enemy soldiers have ransacked their home. On his own return to his home village, Ugwu learns that his sister was gang-raped; he starts penning down his experiences.
The novel ends with Richard and Olanna resigned to Kainene's disappearance. It is also confirmed that the excerpts from The World Was Silent When We Died, which are quoted at various points in the text, can be traced back to Ugwu. In the novel's closing lines, Ugwu dedicates his book to Odenigo.
