In Kabul, prior to the Soviet invasion of Afghanistan, well-to-do young boy Amir and his young Hazara servant Hassan are best friends. Amir writes and reads stories to the illiterate Hassan. Amir's father, Baba, is contemptuous of Amir's writing and regards him as a weakling for letting Hassan protect him from bullies. Baba's friend, Rahim Khan, encourages Amir. Another boy, Assef, confronts Hassan and Amir, but Hassan prevents the attack with a slingshot, a birthday gift from Amir. Assef swears revenge.
Soon the Soviets invade Afghanistan, forcing Baba, a known anti-communist, to flee the country, leaving Rahim Khan as property caretaker. En route to Pakistan, Baba risks his life defending a female refugee from a Soviet soldier who demands to rape her in return for safe passage for all. Baba and Amir eventually reach the United States as refugees in San Francisco, California. Baba tends a gas station while Amir attends community college and vends at a weekly flea market. There, Amir meets Soraya Taheri; Soraya is interested in Amir's writing although her father, the ex-General Taheri, a Pashtun, is contemptuous. Baba becomes mortally ill; he obtains General Taheri's permission for Amir to marry Soraya. They marry happily married despite an inability to conceive children. Amir publishes his first novel.
Rahim Khan contacts Amir, asking him to hurry to Pakistan. Amir arrives to learn that Hassan had become caretaker of Baba's house, but the Taliban executed him and his wife for refusing to abandon the property. Rahim further reveals that Hassan was in fact Amir's half-brother, son of Baba and Ali's wife. Amir reads a letter from Hassan decrying what happened to Afghanistan and asking Amir to one day return. Rahim Khan reveals he wishes Amir to retrieve Hassan's now orphaned son, Sohrab. Amir, overcoming fearful reluctance, arrives in Taliban-controlled Kabul in disguise. Amir's driver helps him observe the difficulties of life under the Taliban.
Tracing Sohrab to an orphanage, they learn that a Taliban official who regularly demands children for nefarious purposes has recently taken Sohrab. Amir and Farid are told that they can meet the official at a football match, where he regularly punishes innocent people. Reluctantly Amir accompanies Farid to a football match in order to see this official, and witnesses a half-time stoning of accused adulterers. Amir arranges an appointment at the official's heavily guarded home and discovers that this is none other than the bully Assef. Despite the ban on music and dancing, Sohrab is presented as Assef's dance boy.
Amir stands up to Assef, demanding Sohrab be released to him. Assef agrees but makes a deal, saying that Amir must fight and win the boy. In the end, Assef beats Amir. Witnessing this, Sohrab, secretly in possession of the slingshot his father received from Amir so long ago, gravely wounds Assef with a bolt to Assef's left eye. Amir and Sohrab escape the house. They flee the country to find that Rahim has died. Sohrab runs away from Amir but is found in front of the biggest Mosque in the world, saying he felt dirty because of what Assef did to him.
Amir takes the traumatized and withdrawn Sohrab back to the US. When General Taheri one night asks why Amir brought "that Hazara boy" back with him, Amir, again standing up to an overbearing figure, informs the General of their familial relationship and demands he never deride Sohrab as Hazara again. Later, Amir shows Sohrab the tricks of kite flying, which he and Hassan used to do in the old days. Slowly Sohrab begins to interact with Amir, who enthusiastically runs the kite, pledging the act to Sohrab.
