Fiction by Khaled Hosseini.
This a fabulous book by the author of The Kite Runner.
The opening chapter has an Afghan father telling a fanciful story to his children before they set out on a journey. The story is about a mythical monster who requires a family to sacrifice one child to him, in order to save the rest of the children.
It's just a story. But soon young Abdullah learns why his father has told him the story, and the hidden purpose of their journey.
Super good book that follows this family through two generations.