Efrén is a seventh grader born in the United States to undocumented parents from Mexico. He is a responsible, diligent student who loves reading books in his only private space: the family bathtub. When his mother is suddenly deported, Efrén must take over caring for his younger twin siblings while trying to manage his schoolwork and heavy emotional burden.

Amá works long hours ironing garments in a factory to support her family. Efrén views her as a "Soperwoman" because she manages the cramped apartment, ensures her children have clean clothes, and makes filling meals from limited ingredients. Her sudden arrest by immigration enforcement sets the central conflict into motion.

Apá is a former police lieutenant who fled corrupt cartels in Mexico to seek safety in the United States. He works multiple construction and overnight jobs to provide for his family, especially after an emergency appendectomy puts them in debt. He pushes himself to exhaustion to fund his wife's return trip across the border.

David is Efrén's best friend and the only white boy living on their block. He favors bright, oversized clothing and lives with his grandmother while his mother works on her sobriety. He runs for middle school president with unrealistic promises, causing friction when Efrén begins taking the election seriously.

Jennifer is a knowledgeable, politically aware seventh grader who occasionally annoys classmates by correcting them. She researches immigration policies because her own mother lives in the country without authorization. She forms a quick bond with Efrén over books and shared family secrets.

Lalo is a deported taxicab driver living in Tijuana who spent decades in the United States. He has a teenage daughter in California whom he can only see through the border wall. He spots Efrén in danger and steps in to provide shelter, food, and crucial guidance.

Max is Efrén's kindergarten-aged twin brother. He misses his mother deeply and occasionally rebels against Efrén's substitute parenting, such as refusing to dress for school and hiding under the sink.

Mia is Efrén's kindergarten-aged twin sister. She feels intensely angry and confused about her mother's sudden absence, questioning why she had to leave.

Mr. Garrett is a middle school history teacher whose recent divorce has left him unengaged and strict. His teaching style transforms completely after he learns about the serious struggles facing his students' families.

Ms. Salas is the Leadership class teacher who oversees the middle school's student government. She supports politically active students and serves as a vital resource for children in crisis.

Doña Chana is a neighborhood resident who watches Max and Mia on the day of the immigration raid. She is the one who breaks the news of the arrest to Efrén.

Ms. Solomon is Efrén's former elementary school teacher. She takes a warm interest in the family and provides emotional support when she learns about their crisis.

Han is a shy middle school student and a close friend of Jennifer Huerta. She supports Jennifer's political ideas but feels too anxious about public speaking to run for office herself.

Abraham is a student at the middle school who passes along important information regarding the presidential race and school vandalism.