Barbara is the 13-year-old daughter of the prestigious Van Laar family, who own Camp Emerson. Resenting her parents' focus on social status and feeling neglected by them, she adopts a punk aesthetic to actively rebel against their expectations. She is resourceful and possesses strong outdoor skills. She longs for genuine connection away from the rigid confines of her family's wealth.

Louise is a 23-year-old counselor at Camp Emerson who bears the heavy responsibility of caring for her younger brother, Jesse, due to their mother's neglect. As a local from a lower-income background, she feels acutely aware of the class divide between herself and the wealthy Van Laars. She works hard to provide for her sibling while managing a fraught romantic relationship.

Tracy is a quiet, 13-year-old introvert who prefers reading alone over socializing. Following her parents' divorce, she feels overlooked by her father and expects to remain an outsider at the summer camp. Her bunkmate's unexpected friendship brings her a new sense of belonging and thrusts her into the center of the camp's unfolding mysteries.

Alice is the matriarch of the Van Laar family, trapped in an emotionally barren arranged marriage dictated by mid-century social expectations. The 1961 disappearance of her beloved firstborn son shattered her mental health, leading to a heavy reliance on prescription sedatives and alcohol. She struggles to bond with her daughter and spends her days heavily medicated, searching for signs that her son is still alive.

Judyta is a rookie investigator and the first female detective on the Albany police force. She approaches her job with meticulous attention to detail and careful observation, often having to manage the condescension of her male superiors. Her ability to build rapport and listen to overlooked witnesses makes her uniquely suited to untangle the web of secrets surrounding the Van Laar family.

Peter is the wealthy and controlling patriarch of the Van Laar family. He is deeply concerned with preserving his family's elite reputation and social standing, utilizing his power to dictate his wife's behavior and shield his family from public scrutiny.

Bear is Alice and Peter's firstborn son, who vanished at the age of nine during the family's annual summer party. His unresolved disappearance casts a long shadow over the Van Laar family and the local community, serving as the tragic catalyst for his mother's emotional decline.

TJ is the pragmatic and skilled director of Camp Emerson. Having grown up on the preserve, she possesses extensive knowledge of the wilderness and survival tactics. She operates outside traditional gender expectations of the era and maintains a complex, subservient professional dynamic with the Van Laar family despite effectively running their property.

John Paul is the Van Laars' godson, currently staying at their estate for the summer. He is positioned to take over a lucrative family business, but his privileged exterior masks a volatile temper and a substance use habit. His actions frequently endanger the people closest to him.

Victor is the former caretaker of the Van Laar property and TJ's elderly father. His livelihood has always depended entirely on remaining in the good graces of his wealthy employers, forcing him into difficult moral and professional positions over the decades.

Jacob, known in local lore as the serial killer "Slitter," is a cunning convict with deep historical ties to the land now owned by the Van Laars. His recent prison escape, combined with his extensive knowledge of the local terrain, coincides alarmingly with Barbara's disappearance.

Carl is a local gardener and hired hand who worked for the Van Laars in the early 1960s. As the last person to admit seeing Bear alive, he quickly becomes the prime suspect in the boy's disappearance before suffering a fatal heart attack during the search.