What would be the call, the threshold, the challenges, the abyss, the transformation, the revelation, the atonement, and the return of this story?
These are some great ideas. Below are my initial responses, but I should point out that there are probably many other possible examples.
THE CALL. Amir gets the call to become a writer after Hassan tells him his own original story is better than the others he has told him. Baba, however, is not impressed.
THE THRESHOLD. Amir finds himself on the threshold of personal greatness when he wins the kite-flying contest, but he reaches a new low that same day when he stands idly by as Hassan is raped.
CHALLENGES. The greatest challenges in Amir's life seem to come after he moves to California. He make a new life for himself, goes to college, meets a girl, writes successfully, and enjoys a true father-son relationship with Baba.
THE ABYSS. Three examples come to mind: (1) Amir regrets his decision to not come to Hassan's aid when he is raped. (2) He further regrets his traitorous and underhanded planting of the "stolen" birthday gifts under Hassan's bed. (3) Their departure from Kabul and the harrowing trip through Afghanistan in the vile tank of the oil truck is a true example of the hell they face.
TRANSFORMATION. Amir turns his life around in California, becoming a successful writer and marrying a woman he truly loves. His relationship with Baba also improves dramatically.
REVELATION. Amir discovers Hassan is his half-brother, fathered by Baba. Hassan also has a son somewhere in Afghanistan. Baba's life has been a lie, Amir decides.
ATONEMENT. Amir returns to his Taliban-held homeland, locates Sohrab, and escapes with him to Pakistan and then California, where he makes the boy a part of his family.
THE RETURN. This relates to his atonement (above), but more importantly, it marks the return of Sohrab to a civilized world with a family who cares for him. It also marks the reunion of the kite running, this time with Amir running for his old friend's son.