Sophie is a 35-year-old former lifestyle editor who recently relocated from Chicago to Mapleton, Texas. She lives with her husband and young son. Struggling with boredom and the transition to being a stay-at-home mother, she develops an intense fascination with a wealthy local woman named Margot Banks. Sophie is drawn to the glamour of Margot's elite social circle and attends weekly target shooting sessions at a remote lake house, ignoring her own boundaries to secure her place in the group.

Margot is a wealthy and influential woman in Mapleton's elite society. She curates an idealized, glamorous image on social media that immediately captivates Sophie. Margot commands a tight-knit clique of married women who meet at her lake house to drink and shoot clay targets. She rules her social circle with strict rules and demands absolute loyalty from her friends.

Jill is a prominent member of Margot's exclusive inner circle. On the surface, she is a wealthy homemaker who enjoys an active social life with her husband. She harbors quiet tension regarding Margot's behavior toward her teenage son, Brad. She is fiercely protective of her son and highly invested in his college plans.

Callie is a fiercely loyal member of Margot's clique. She is highly possessive of Margot and deeply suspicious of newcomers. She views Sophie as a threat to her position in the social hierarchy. She frequently gives the new arrival a cold shoulder and makes her disapproval evident to the rest of the group.

Brad is Jill's teenage son. He is a popular high school student who dates a girl his age named Abby. He also draws inappropriate attention from his mother's friend, Margot. Brad is caught between the expectations of his family, his actual girlfriend, and the manipulative influence of Mapleton's adult socialites.

Graham is Sophie's devoted husband and a professional architect. He offers Sophie the stability she lacked in her childhood. He initially supports his wife's attempts to make friends and integrate into Mapleton society. He remains largely unaware of the illicit activities that define the weekly gatherings at the lake house.

Erin is Sophie's grounded friend from the brief time Sophie lived in Mapleton as a teenager. Happily settled with her husband and child, Erin serves as a sharp contrast to Margot's chaotic social circle. She actively warns Sophie about Margot's snobby reputation, though her advice goes ignored.

Tina is the most easygoing member of Margot's inner circle. She attends the late-night excursions with the other women but claims to be happily married and only participates as a spectator. She often acts as an informal guide for Sophie, explaining the group's history and internal dynamics.

Jamie is a local high school student and Brad's close friend. He frequently accompanies Brad to the lake house and inserts himself into the adults' social gatherings. He flirts with older, married women and shows a reckless disregard for boundaries.

Abby is Brad's teenage girlfriend. She is a normal, age-appropriate partner for him but becomes an unintended rival for the attention of older women in Brad's life. Abby struggles with her mental health and relies heavily on Brad for emotional support.

Jack is Sophie and Graham's young son. The family's move to Texas is largely motivated by Sophie's desire to give him a quieter, safer childhood away from the city.

Ryan is Erin's husband. He hosts neighborhood barbecues and provides a stable, conventional family environment that mirrors Graham's ideal life for Sophie.

Harold is a local Mapleton resident who lives near Sophie and Graham. He is occasionally seen watching Sophie through binoculars while she jogs on the nearby trails.