On the way back from signing up for the army, Tayo remembers that the family understanding has always been that Rocky will one day leave, but that Tayo will stay at home to help. At this realization, Tayo is reminded of the great feeling of loss he had at his mother's death. Josiah and Grandma think Tayo should go with Rocky, and so Auntie has to agree.
While they were in high school, Josiah invested in a herd of cattle. He bought them in Sonora, Mexico, from Ulibarri, a cousin of Night Swan, his Mexican girlfriend. Josiah was sure that the Mexican cattle were a better investment than the Herefords that others tried to raise because they were used to the desert. He tried reading books that the agricultural (ag) extension office sent him, but he found they were only suited to big farms away from the desert. Tayo loved the idea of the cattle because Josiah included him in the plans. Rocky mistrusted it because he believed the scientific books of the ag extension. Auntie mistrusted the idea because it was connected to the Mexican girlfriend.
A week later, the cattle are delivered to the Laguna reservation. Josiah lets them out near an area where the grass is still green. A week after that, when they return to check on the cattle, they find that they have broken through a fence and moved south. The men are woe to keep track of the cattle, but the animals continue to move slowly south and are very difficult to round up. As they get closer to Mexico, Josiah decides to brand them. He is able to catch and brand them, but they continue heading south. Josiah does not want Auntie and Grandma to know of his troubles.
The story/poem continues. Fly appears in the jar, and Hummingbird says they will go together. They go four worlds down and find everything growing and beautiful.
One day when Josiah goes to Lalo's store to get bootlegged beer, he sees a Mexican woman and falls in love with her. He returns the next day, and Night Swan invites him upstairs with her. She dances flamenco for him and tells him of how she used to dance and make men love her when she was younger. Night Swan is a grandmother now, and says that now when she dances it is for her granddaughters. But when the drought struck in Mexico, she moved north, and stopped near the Laguna reservation and Cubero because she liked the look of the mountain. At first, the Cubero women were upset because they imagined their husbands were going to see her, but they relaxed when they realized Josiah was with her every night. When Auntie finds out about Josiah and Night Swan, she is outraged, saying that it will bring shame on the family and upset old Grandma. But old Grandma doesn't mind people gossiping about her family as long as she has better gossip about them, which she usually does.
Tayo continues to help Josiah keep the cattle on Laguna land and to check on the sheep. They spend the summer this way, while Rocky relaxes. He has a football scholarship to college. After dinner, Josiah goes to visit Night Swan. Auntie compares Josiah's wandering to their old dog, which was hit by a car while it was following a bitch in heat. Tayo remembers how Josiah comforted him at his mother's funeral.