Answer: They became poor immigrants due to a chain of unfortunate events. The first one to befall upon them was the murder of Esperanza's father by bandits, which flung Esperanza's life upside down. Without her father to support her family, Esperanza's uncle and Papa's brother, Tio Luis, offered to marry her mother in attempt to seize their family's riches and property. After much indecision and uncertainty, Mama decided that it was best for her, Esperanza, Miguel, Alfonso, and Hortensia to move to California for the time being. It was there that the group became poor migrants, so unlike their wealth in el Rancho de las Rosas, and worked day and night for little pay and terrible conditions.