Shay is a highly intelligent data analyst and market researcher living in New York. She struggles with profound loneliness, having recently been downsized from her job and harboring unrequited feelings for her roommate. She processes the world around her by recording statistics and observations in a data notebook. Her isolation makes her exceptionally receptive when a glamorous group of women takes an interest in her.

Cassandra is the elegant, confident co-owner of a boutique public relations firm in New York. She projects wealth, status, and an effortless magnetism that immediately draws people to her. Alongside her sister Jane, she commands a close-knit, highly guarded circle of women who share a bond forged by past traumas and a desire for vigilante justice.

Jane is the co-owner of a successful PR firm alongside her sister Cassandra. Described as softer and curvier than her sister, she nonetheless possesses the same commanding, chic presence. She uses her charm and interpersonal skills to identify vulnerable women and welcome them into the sisters' influential sphere.

Amanda is an emergency room nurse with an effervescent personality whose tragic death sets the plot in motion. Her work with assault victims left her frustrated by the lack of legal accountability for perpetrators. Before her death, she was a key member of the Moore sisters' inner circle, valued for her medical access and caring nature.

Valerie operates in the shadows as a capable, do-it-all assistant for Cassandra and Jane's public relations firm. A former Los Angeles actress with a history of being bullied, she is highly skilled at adopting aliases and running covert errands. She manages the logistics and surveillance tasks required to keep the sisters' group secure.

Stacey is a self-taught cybersecurity consultant who handles technical surveillance for the Moore sisters. After dropping out of high school, she rebuilt her life but found herself facing assault charges after defending a neighborhood child from an abuser. The Moore sisters intervened during her legal crisis, earning her permanent loyalty.

Beth is a public defense attorney who often appears slightly flustered and overwhelmed by her workload. She was abandoned by her husband during a battle with breast cancer. The Moore sisters provided her with crucial emotional support during this vulnerable time, and she now uses her access to legal records to assist their circle.

Daphne owns a chic, high-end clothing boutique in the West Village. She is a survivor of a brutal sexual assault committed by a man she met on a blind date. Fearing the police would not believe her, she kept the assault hidden until she found solace and fierce backing from the Moore sisters.

Sean is Shay's roommate and one of her only genuine friends in New York. Unaware that Shay harbors romantic feelings for him, he continues to share their apartment while his relationship with his girlfriend grows more serious. He is a kind, grounded presence who respects Shay's intelligence.

Jody is Sean's girlfriend who works as a professional organizer. She is exceptionally neat and controlling of her environment. She actively dislikes Shay, openly describing her data-collecting habits as "creepy," which creates a tense dynamic in the apartment as she begins moving her belongings in.

James is a serial predator who went on a blind date with Daphne ten months ago, ending the night by brutally assaulting her. He is later found dead under suspicious circumstances in Central Park.