Esperanza Ortega was a wealthy girl who had everything she wanted and had a loving mother and father whom she loved. One day, her father and some of his men are suddenly killed by bandits, while he is out working at their ranch. Her father intended to leave everything to his wife, Ramona,and Esperanza Ortega, but the family lawyer informs them that a loophole in the will states that the ranch, where most of the money comes from, will go to Señor Ortega's step brother, Luis Ortega, whom Esperanza calls Tío Luis, who is implied to have a hand at Señor Ortega's murder. He plans to go into politics even deeper, and feels that with Ramona, a famous wealthy socialite loved by many in their town, will look good on his side and offers to marry her. She refuses, and he subtly threatens that bad things will happen if she does not marry him.
Their mansion later burns during a mysterious fire and Tío Luis returns and re-offers his wedding proposal. Ramona accepts, under the condition that he rebuilds the mansion and sends her money and a wagon to visit her mother, Abuelita. Esperanza openly tells him she dislikes him, and he says the moment he becomes her stepfather, he will send her to a boarding school. Later on, Ramona tells Esperanza that she is not planning to marry him, and plans to escape to America. With the help of Abuelita (Esperanza's grandmother), Alfonso, Miguel, and Hortensia (all servants for Esperanza) they trick Tío Luis to give Ramona money and necessities, and escape with the help of their loyal servants to cross the border. They leave Abuelita in the mansion because of her injured ankle. Abuelita promises to return to them after she heals, though. Despite what happened, Esperanza and her family must migrate to the United States. Unfortunately, they move during the Great Depression. Now Esperanza learns to face conflicts and rise above them. Ramona and Esperanza live in a poor Mexican labor camp in Arvin, California with their servants and their family. Ramona adjusts to a poor life, but Esperanza's attempt to hold on to her memories are laughed upon by the poor children, especially a poor girl named Marta. Many terrible things happen, but with the help from her family she tends to face the bad things.
Ramona, along with their former servants, get a jobs in a field, while Esperanza stays home with her servants cousins (Isabel, a young girl, and Pepe and Lupe, both babies). When a dust storm occurs, Mama gets sick (with valley fever) so she must move to a hospital. Unable to afford the hospital bills, Esperanza gets a job cutting out potato eyes. Esperanza then gets a better job, to get a bus ticket for Abuelita, pay for the hospital bills, and take care of the household. However, upon learning that Ramona (Mama) is better, and Esperanza has saved enough for Abuelita, Esperanza finds that a friend has stolen her money. Days later Ramona is better, her friend, Miguel, has gotten a surprise at a bus stop. Esperanza, Alfonso, and Hortensia go to the bus stop as told. They then learn that Miguel has used the money to go to Mexico and get Abuelita.