The Circuit by Francisco Jimenez is about a Mexican boy named Francisco and his family. They cross the border from Mexico to California for a better life as migrant workers. They pack up and move each season to find work only to endure hardships and the struggle of having to start over every few months.

Francisco and his family pass under a wire fence to steal across the border from their native Mexico to California. Once they arrive, work is hard to find. Papa and Roberto, Francisco's older brother, are migrant workers who pick cotton, strawberries and grapes when in season. They move from place to place, eventually ending up in Tent City, a migrant worker camp of tent homes, in Santa Maria. There is no electricity or plumbing. Francisco attends his first American school there. Much to his surprise, his teacher does not speak Spanish. Everyone speaks English and he must too. Francisco mostly stays in his own thoughts during class time and does not accomplish much. He wins a blue ribbon for his butterfly drawing, but he must repeat the grade.

Francisco's new baby brother, Torito, gets very sick and almost dies in Tent City; it is a miracle he lives. The family keeps moving all over California to find work. Francisco wants to have his own cotton sack very much so he can pick with Papa and Roberto to help out the family. Although he fails at the first attempt, he does get a sack. He joins Papa and Roberto picking in the summer months and during certain seasons. He grows tired of picking and instead focuses on the grammar rules of English.

Francisco continues to attend school and starts to learn English words. His favorite teacher, Mr. Lema, sits patiently with him and helps him learn English words during lunch. He promises to show Francisco how to play the trumpet the next day, but Francisco's family leaves town that day. Meanwhile, Mama keeps giving birth to children.

Francisco is excited because the family finally moves back to Bonetti Ranch in Santa Maria. It is an old barracks settlement, but it is a home to him. Papa cannot work anymore due to his bad back. So Roberto gets a janitorial job in the school. This means the family can stay in Santa Maria. Everyone is happy.

Francisco goes to school and starts to learn more English in the eighth grade. His big class assignment is to learn a portion of the Declaration of Independence. He memorizes it and is excited to recite it to his teacher. As he sits in class that day, immigration comes in and gets him. Francisco sits in the back of the immigration car as they go to find Roberto.