Evan is a sensitive twelve-year-old Chinese American boy who moves to a small Virginia town after his father abandons the family. He possesses a unique physical sensitivity to lies, which makes him literally sick when people are untruthful. Adjusting to a predominantly white community steeped in Civil War history proves difficult, but Evan seeks to find his own place and uncover overlooked historical truths.

Celeste is Evan's fifteen-year-old sister, a high school freshman who dresses primarily in black. She is fiercely protective and observant, openly expressing her frustration over their family's sudden relocation. Unlike her brother, she resists trying to fit into Haddington's culture, preferring to maintain her independence and critique the prejudices around her.

Elaine is the devoted mother of Evan and Celeste who uproots her family to Virginia for a fresh start. Working as an office manager, she struggles to maintain financial and emotional stability following her husband's betrayal. She acts overprotective of her children, frequently emailing their teachers to monitor their adjustment to the new school.

Max is a confident middle school student and the son of the local police chief. Secure in his social standing, he quickly befriends Evan and introduces him to the town's traditions, such as Battlefield Day. He struggles to balance his new friendship with his past connection to Brady, feeling conflicted about standing up to bullying.

Brady is a classmate of Evan who acts hostile and defensive toward the new student. Burdened by his family's poor reputation in the town, he lashes out at others to deflect from his own insecurities. Despite his abrasive behavior at school, he possesses an affinity for working with dogs.

Charlie is Brady's nineteen-year-old brother, characterized by his volatile temper and menacing presence. He drives a black car decorated with flames, skulls, and the words "No Mercy." He holds onto exclusionary beliefs and serves as an intimidating figure in the community.

Michael is Evan and Celeste's father, who abandoned the family after orchestrating a financial scam in California. Though absent from their daily lives in Virginia, his actions cast a long shadow over the family. His betrayal leaves his children confused and hurt.

Joe is Elaine's pragmatic and supportive brother who works as an electrician in Haddington. He serves as a stabilizing presence for his niece and nephew, teaching Evan hands-on skills. He offers straightforward advice and encourages the family to adapt to their new environment.

Mrs. Norwood is a teacher at Battlefield Middle School who organizes the annual Battlefield Day reenactment. While generally well-meaning, she holds blind spots regarding the inclusivity of her assignments. She unintentionally alienates Evan by pushing him toward a behind-the-scenes role.

Randall is the father of Brady and Charlie Griggs. He maintains a rigid and often harsh household, prioritizing the family's reputation over emotional support. His strict parenting style deeply affects his sons' behavior.

Chief Baldwin is Max's father and the local police chief. He holds a position of authority in Haddington but often displays indifference toward the prejudice affecting marginalized residents, avoiding prosecuting minor offenses when he deems them inconvenient.

Mochi is a brown stray dog that Evan and Joe discover near an ice cream shop. She quickly becomes a beloved member of the Pao family. She provides Evan and Celeste with comfort and unconditional acceptance in their new town.

Martha is a local real estate agent in Haddington who helps Elaine find a home. She harbors stereotypical expectations about the Pao family, hoping they will exhibit behaviors she considers culturally interesting.

George is a friendly librarian and an acquaintance of Joe. He enthusiastically helps Evan research historical records about Chinese soldiers in the Civil War, connecting him with valuable resources.

Julia is a thoughtful classmate of Evan. Inspired by Evan's research, she pushes back against conventional narratives and chooses to study a woman who disguised herself to fight in the Civil War.