The "overture" and "exposition" have the same role within a narrative text, or in a prose. This is because these two terms refer to an introduction to the plot of the story, where the characters will be presented, the scenario and even the main subject of the narrative.
He used to be embarrassed by his grandpas appearance, but through out the story he learns to cope with who he is and his Indian heritage. He also doesn't mind the medicine bag anymore.