Leah is a fourteen-year-old girl living in a rented, uninsulated cottage in Supply, North Carolina. She experiences undiagnosed medical episodes she calls "spells" that resemble epilepsy. A keen observer of the natural world, she spends her time studying local flora and fauna and hopes to build a house on the beach someday. Following her father's fatal work accident, she is relocated to Matthews, North Carolina, where she is pressed into working as a domestic helper.

Jesse is the only son of the wealthy Barna family. He frequently explores the woods with Leah and supports her dreams of moving to the beach. He lacks the confidence to defend Leah against their classmates when they tease her about her lower-class background. Despite this public distance, he proves to be a loyal confidant in private and maintains a steady correspondence with her through hidden letters.

Mrs. Griffin is an affluent, heavily styled woman who takes Leah into her home under the guise of charity. She secretly intercepts Leah's mail, denies her an education, and forces her into the role of an unpaid housemaid. She is obsessed with maintaining a perfect public image and ascending the social ladder. She heavily disciplines her children and judges them harshly for failing to meet her high standards.

Harley is a hardworking lumberjack who clear-cuts land for development in coastal North Carolina. He struggles to provide luxury items for his daughter but creates a secure, loving environment in their small cabin. He gifts Leah a sapling and a seashell every year for her birthday in memory of his late wife.

Mr. Griffin is a traveling salesman who provides a comfortable financial life for his family. He often visits Raleigh for work, a habit that deeply irritates his wife. He is entirely passive at home, routinely ignoring his wife's mistreatment of their children and Leah. He prefers to sidestep conflict rather than enforce fairness under his own roof.

Michael Henry is the oldest Griffin child. He struggles to maintain good grades in school, which draws constant ire from his mother. He wants to pursue a career in sales like his father, but his mother insists he become a lawyer. He occasionally treats Leah with kindness and asks her to teach him how to dance before a local ball.

Eva Jane is the middle child of the Griffin family. She fixates on material possessions, expensive dresses, and her upcoming debutante ball. She suffers through her mother's harsh criticisms regarding her weight and physical appearance. She teaches Leah a fortune-telling trick with an apple peel but largely views Leah as a social inferior.

Mary Ann is the youngest Griffin child. She frequently finds herself locked in her room without food as punishment for minor infractions like wetting the bed. She develops a quiet, trusting connection with Leah, sneaking her food and asking innocent questions about her life.

Tulla is the elderly housemaid who works for the Barna family. Though small in stature, she is physically strong and easily manages demanding domestic chores. She offers Leah genuine maternal warmth, gives her art supplies, and teaches her practical skills like cooking and gardening.

Mr. Barna is a wealthy landlord and prominent business owner in Brunswick County. He rents a humble cottage to Leah and her father. After a tragedy strikes the Payne family, he transports Leah across the state to her new placement with the Griffins.

Mrs. Barna is Jesse's mother. She enjoys a life of comfort in a large, well-furnished home. She once made a promise to Leah's mother to look out for the girl, which influences her decision to temporarily take Leah in after a fatal accident. She ultimately arranges for Leah to move away, believing the girl needs proper foster care.

Emma is Leah's late mother. She grew up as a wealthy debutante in Raleigh before eloping with Harley. She died in childbirth, leaving behind a beautiful, hand-stitched quilt that becomes Leah's most prized possession.

Maeve is a stray cat that lives on the Barnas' property. She accepts food from Leah and frequently seeks warmth inside the uninsulated cottage. The Barna family continues to care for the cat after Leah moves away.

Dr. Foster is a physician practicing in Matthews. He advocates for a eugenics program designed to genetically cleanse society. He uses his medical authority to evaluate young women and relies on affluent society ladies to distribute pamphlets about his work.

Alma is an older woman who previously worked as a helpmate for the Griffin family. Mrs. Griffin dismissed her from the position after Alma refused to withhold food from a punished Mary Ann.

Tom is a student at the local school in Supply. He actively bullies Leah regarding her lower-class status and her academic difficulties, frequently tripping her when she walks past his desk.

Mrs. Wemberton is an affluent woman in Matthews who socializes with Mrs. Griffin. She places immense importance on introducing daughters into society through debutante balls, which heavily influences Mrs. Griffin's parenting.