He asked an old merchant if he has seen a hazara boy and he replied that he went south and that the boys who chased him probably caught him by now. Amir continued to search and eventually found Hassan in an alley. He saw Hassan holding the blue kite while he was surrounded by the bullies Assef, Kamal and Wali. Amir did not intervened, instead he observed from around the corner. He heard Assef say to Hassan that they would let him go if he gave the kite to Assef, but Hassan refused to because he wanted to give the kite to Amir. Assef and his friends pushed Hassan against the snowy ground and took off his pants while Assef did the same thing. Amir saw his best friend get raped and was considering to intervene but instead he ran away. He ran away because he was scared to get beaten up and he wanted the dragon that would prove that he was a winner just like his father and thereby win his love and approval. In the book Amir says: "I actually aspired to cowardice, because the alternative, the real reason I was running, was that Assef was right: Nothing was free in this world. Maybe Hassan was the price I had to pay, the lamb I had to slay, to win Baba." (p. 68).
After a while Amir saw Hassan coming towards him with the kite in his hand. Amir pretended to look for Hassan who was crying and bleeding. He handed Amir the kite and neither boy spoke about what happened. After the rape Amir got so tortured by the fact that he betrayed his best friend that the friendship with Hassan ceased, they neither talked or spent time with each other after that. This event is the turning point of the entire story as both Hassan's and Amir's life changed. I think that the book is mostly named after this particular event because it has such an important meaning for the future of the book. Ever since Amir's betrayal kite fighting has reminded him of his treachery. When Amir later moves to the U.S he gets told that Hassan is dead which makes Amir even more anxious.