Tyler is an 11-year-old boy who loves his family's farm, astronomy, and participating in his 4-H club. Grieving the sudden death of his grandfather from a heart attack, he is alarmed to discover his parents have hired undocumented Mexican workers to save their property following his father's incapacitating tractor accident. He questions the legality of this decision, weighing his ingrained patriotism against his growing empathy for the new workers, particularly his classmate Mari. He tracks constellations through a telescope his grandfather gave him, finding comfort in the stars.

Mari is the 11-year-old eldest daughter of one of the newly hired farm workers. Born in Mexico, she worries about her undocumented status after crossing the border at age four with the help of coyotes. She acts as a responsible caretaker for her two younger, American-born sisters and serves as a translator for her father. Deeply missing her mother, who went back to Mexico to visit a dying relative and subsequently disappeared, Mari documents her fears and hopes in detailed letters she cannot safely mail.

Tyler's grandmother lives independently on the Paquette farm property following the sudden heart attack of her husband. She finds companionship in the three young Cruz daughters, who teach her about Mexican traditions and help her set up a Day of the Dead memory table. She fiercely defends her independence against her daughter Aunt Jeanne's attempts to move her into an assisted living facility. Grandma demonstrates an open-minded and generous attitude toward the immigrant workers, frequently inviting them into her home.

Tyler's parents face severe financial hardship after Mr. Paquette suffers an incapacitating tractor accident early in the summer. Desperate to keep their multi-generational dairy farm running, they make the legally risky decision to hire undocumented Mexican workers. Mrs. Paquette tries to manage the household and smooth over cultural tensions by sending board games to the workers' children, while Mr. Paquette struggles with physical limitations and bitterness over his accident.

Mari's father takes demanding construction and farm jobs in the United States to send financial support back to his family in Mexico. He lives in constant fear of immigration authorities and strictly monitors his daughters to keep them safe from detection. The prolonged, unexplained disappearance of his wife leaves him emotionally strained, causing him to enforce strict rules, such as demanding his daughters only watch Spanish-language television to preserve their heritage.

Mari's mother is deeply missed by her family after disappearing eight months before the family moves to Vermont. She traveled back to Mexico alone to visit her dying mother and vanished while attempting to return to the United States. She serves as the emotional anchor for Mari, who constantly writes letters to her in hopes that she will eventually find her way back to the family.

Tío Felipe is Mari's young uncle who travels to Vermont with his older brothers to find agricultural employment. He works long hours in the milking barns to send money back to his aging parents in Las Margaritas, Mexico. He maintains a good-natured, youthful demeanor despite the harsh conditions of their labor. He enjoys playing his guitar, Wilmeta, bringing a sense of lightness and cultural celebration to the family's highly stressful circumstances.

Luby is Mari's youngest sister. Because she was born in Durham, North Carolina, she is a legal United States citizen. She is accustomed to American comforts and sometimes struggles to understand the severe danger her older sister and parents face regarding deportation.

Ofie is Mari's middle sister, also born in the United States. She enjoys American television and snacks, which sometimes causes friction with her father's intense desire to preserve their Mexican heritage. She is highly vocal about her opinions and frequently expresses how terribly she misses their missing mother.

Tyler's deceased grandfather passed away from a heart attack shortly before the summer began. He was a guiding figure for Tyler, teaching him about star navigation and gifting him his prized telescope. Grandma and the Cruz girls set up a Day of the Dead altar to honor his memory, and Tyler frequently looks to the sky believing his grandfather is watching over the farm.

Mr. Bicknell is Tyler's favorite teacher at Bridgeport Elementary School. He encourages his students to think critically about history and their local community. When town residents question the presence of undocumented workers in Vermont, Mr. Bicknell provides historical context about the town's own immigrant roots, reminding the community of their shared origins.

Mr. Rossetti is an elderly, cranky resident of the Vermont town who holds strong anti-immigrant views. He speaks out against the presence of undocumented workers in the community and threatens to expose locals who hire them. His outspoken nature creates significant anxiety for Tyler, who worries his parents will be arrested.

Mrs. Ramirez teaches Spanish at Tyler's middle school. She is a helpful community member who introduces local students to Mexican customs like the Day of the Dead. She later uses her bilingual skills to assist the Paquette and Cruz families by serving as a translator during a critical legal meeting.

Aunt Jeanne is Tyler's aunt and Grandma's daughter. She firmly believes her aging mother should no longer live alone on the farm. She actively tries to coerce her siblings and in-laws into forcing Grandma out of her house and into an assisted living facility or family member's home, causing significant Thanksgiving drama.

Tío Armando is another of Mari's uncles who travels with the family from North Carolina to Vermont. He works long hours in the milking barns alongside Papá and Tío Felipe to earn money for his family in Mexico. He is a quiet but steadfast presence who helps shoulder the physical labor on the Paquette farm.

Ben is Tyler's older brother who plans to leave for university in the fall. He is somewhat disconnected from the immediate farm crisis but occasionally interacts with the younger workers, such as taking Tío Felipe to a university party. He offers pragmatic suggestions during family dinners regarding the new workers.

Sara is Tyler's 15-year-old older sister. She acts kindly toward the Cruz girls upon their arrival at the trailer, bringing them spare clothes. She shares her lip gloss, blush, and hair clips with Mari to help the sisters feel welcome in their new environment.