Mallory is a twelve-year-old, biracial (part Korean) seventh grader at Gibbons Academy in Norwell, Florida. She struggles with social anxiety and relies heavily on conforming to the expectations of her popular friends to feel secure. Though naturally curious, she represses her true interests and distances herself from her ethnic identity out of fear of standing out among her predominantly white peers.

Jennifer is a new Chinese American student at Gibbons Academy who recently moved from Chicago following her father's death. She passionately believes in extraterrestrial intelligence and uses this interest to cope with her grief and search for meaning. She embraces her individuality and refuses to suppress her hobbies or identity, even when facing judgment from her peers.

Reagan is the leader of Mal's popular friend group at Gibbons Academy. She projects an intimidating, confident exterior to hide her deep-seated fears of abandonment stemming from a difficult home life. She acts fiercely protective of Mal but uses exclusionary tactics and cruelty to maintain control over her social environment.

Ingrid is a highly intelligent, method-oriented student at Gibbons Academy. Once close friends with Mal, she has become guarded and somewhat cynical after enduring ongoing bullying. She applies strict scientific principles to mysteries and is unafraid to call out hypocrisy or injustice when she sees it.

Kath is a Black and Jewish student who serves as the first-chair violinist and president of the school's Audio Tech Club. She experiences frequent microaggressions from her classmates but maintains an optimistic outlook on humanity's potential for progress. She actively supports her friends and looks for the good in others.

Tess is a tall, sharp-featured student who belongs to Mal and Reagan's popular clique. She thrives on gathering and spreading sensational rumors to elevate her own status. She frequently uses her religious background to judge others and intentionally pokes at her friends' sensitive spots to maintain a position of power.

Leah is Mal's biracial (half-Korean) mother. She previously dreamed of becoming an Asian American studies professor but relocated for her husband's career. She encourages Mal to be kind, embrace her heritage, and stand against stereotypes, though she notices her daughter pulling away as she gets older.

Mr. Moss is Mal's father, a quiet and religious man who provides a steady presence in her life. He often allows Mal the space to draw her own conclusions rather than forcing his opinions on her, creating a safe environment for her to process her anxieties.

Rebecca is Jennifer's mother, a widow seeking a fresh start for her family in a small Florida town. She dresses brightly and stands out from the conservative locals. She deeply loves her daughter but worries about Jennifer's eccentricities drawing negative attention.

Pete is a privileged student at Gibbons Academy and the son of the local sheriff. He uses his physical size and his father's authority to swagger through the school and town without consequence. He frequently targets unpopular students, employing racist and sexist remarks to assert dominance.

Principal Vaughn is the head of Gibbons Academy. He promotes the image of the school as a loving, close-knit family, though his idealized view fails to recognize the systemic bullying and exclusion occurring in his hallways.