The initial setting is in San Francisco, where the adult protagonist, Amir, recollects his childhood in Afghanistan. He refers to a specific incident that occurred when he was 12 as determining the course of the rest of his life.
Amir was the son of Baba, a wealthy Pashtun merchant, and a beautiful mother who died in childbirth. Amir has a companion and servant, Hassan, who is a member of a religious (Shia) and ethnic (Hazara) minority. The initial chapters of the book describe the inequality in the relationship, in both material goods and power.
The major conflicts in the book are foreshadowed when the neighborhood bully Assef threatens the two boys. The crucial incident, occurring slightly later, is the kite-fighting tournament, which Amir wishes to win to impress his father. With the help of Hassan, he is on the verge of winning by collecting a blue kite, when Assef and two other bullies try to steal the kite from Hassan, and end up taunting and eventually raping Hassan, while Amir is too scared to interfere. It is that act of cowardice which is the important incident and secret shame that shapes Amir's future life.