The novel begins in 2001, with Amir alluding to a phone call he received from his father’s friend Rahim Khan. He recalls something that happened in 1975, back when he lived in Afghanistan with his father, his father’s servant Ali, and Ali’s son Hassan. Ali and Hassan are Hazaras, and Amir is Pashtun. Baba, Amir’s father, is a successful businessman, and Amir never quite feels like he can live up to Baba’s expectations for him. He sees an upcoming kite tournament as a chance to make Baba proud.
Hassan is the best kite runner in Kabul, and doggedly loyal to Amir. Amir is slightly jealous of Hassan’s athletic abilities and his father’s kindness to him. Amir likes to read and write, but Baba has no patience for such things. Amir wins the tournament, and Hassan goes to run the final kite. When Amir goes to search for him, he finds him in an alley with Assef, a local bully who idolizes Hitler. He watches as Assef rapes Hassan, but he is too afraid to intervene.
Amir is ashamed for not helping Hassan, and avoids him. Eventually, he frames him for stealing and while Baba forgives him, Ali and Hassan leave anyway. In 1981, Baba and Amir flee the fighting in Afghanistan for California, where Baba works at a gas station. Amir graduates high school, and meets and marries Soraya, the daughter of a formerly powerful General. Baba dies of lung cancer, Amir becomes a writer, and Amir and Soraya discover they cannot have children.
In June 2001, Amir receives a call from Rahim Khan telling him that there is a way to be good again. Amir returns to Afghanistan to discover that Hassan had a son who is now orphaned after Hassan and his wife were killed. He also learns that Hassan is Baba’s son, his half-brother. Sohrab has been taken by Assef, who is now a Taliban official, and he is being sexually abused. Amir confronts Assef, who beats him viciously until he is saved when Sohrab shoots Assef in the eye with his slingshot.
Amir escapes with Sohrab, but Amir is badly injured. Farid brings him to a hospital in Peshawar. Initially, Rahim Khan told Amir that there was a couple who ran an orphanage in Peshawar who would take care of Sohrab, but he soon discovers that no couple ever existed. Rahim Khan was in poor health and has probably passed away. Amir takes Sohrab to Isalamabad, where he finds that Sohrab is withdrawn and afraid of being abandoned.
Amir and Soraya agree to bring Sohrab to America, but they are stonewalled by the American embassy because there is no way to prove Sohrab is an orphan. Amir tells Sohrab he might have to go back to the orphanage, and Sohrab attempts to commit suicide. Amir finds a way to get him back to the U.S. They arrive in California, and Sohrab remains silent until they go kite-flying one day. Amir offers to run Sohrab’s kite,”a thousand times over,” echoing Hassan’s own words to him.