Janie is a fifteen-year-old high school student living in suburban Connecticut. She has a mass of wild, curly red hair and a dreamy, sometimes passive personality. Her life turns upside down when she recognizes herself on a missing child milk carton under the name Jennie Spring, sparking an agonizing search into her past and identity.

Reeve is Janie's next-door neighbor and a high school student who drives a Jeep. He feels like an academic outcast in his high-achieving family but begins working harder to improve his grades. He becomes Janie's primary confidant and partner as she investigates the milk carton mystery, offering a grounded presence to balance her panic.

Miranda is Janie's elegant, highly structured mother. She dedicates her time to volunteer work and maintains tight control over her household's routine and diet. Beneath her strict, capable exterior lies a deep vulnerability tied to family trauma from her past.

Frank is Janie's father, an accountant who also coaches a local soccer team. He is a good-natured, playful man who often jokes with his family but becomes fiercely protective when they face threats. Like his wife, he hides underlying emotional pain regarding his family history.

Hannah is Frank and Miranda's estranged daughter who left her family to join a Hare Krishna cult. She exists primarily in the memories of the Johnson family, presenting a complex figure whose past choices cast a long shadow over Janie's present reality.

Sarah-Charlotte is Janie's best friend. She is highly organized, decisive, and maintains neat, white-blonde hair. She expects straight answers and clear actions, which makes it difficult for the dreamy, confused Janie to confide in her about the milk carton.

Lizzie is Reeve's older sister. Known for her intelligence and serious demeanor, she becomes involved in Janie's situation when Reeve turns to her for help analyzing the confusing details of the kidnapping.

Adair is one of Janie's close high school friends. She recently obtained her driver's license, an achievement that highlights Janie's inability to secure hers due to missing paperwork.

Mrs. Shields is the Johnsons' next-door neighbor and mother to Reeve and Lizzie. She provides Janie with outside perspective on Miranda's strict parenting style during Janie's early childhood.

Mrs. Spring is the mother of the New Jersey family listed on the missing child milk carton. She lives in a loud, bustling home with several red-headed children and mourns her missing daughter.

Dave is a high school student who attends an academic breakfast with Janie. He attempts to flirt with her, but Janie's internal crisis leaves her unable to answer basic questions about her own life.