Grace is a twenty-eight-year-old prison inmate serving time for a murder she claims she did not commit. Underneath her calm exterior, she harbors a deep rage stemming from the severe mistreatment of her late mother. She dedicates her life to meticulously planning a violent revenge against the wealthy paternal family that abandoned them to poverty.

Simon is an immensely wealthy businessman who abandoned Grace's mother upon discovering her pregnancy. He expects constant deference from everyone around him and uses his vast fortune to insulate himself from consequence. He treats his romantic partners and family members as disposable accessories.

Jimmy is Grace's closest childhood companion. Raised in a comfortable and educated environment, he provides Grace with her only genuine emotional connection. He is empathetic but often allows others to dictate the terms of his life, and his romantic choices create significant friction with Grace.

Kelly is an inmate at Limehouse prison serving a sentence for blackmailing married men. Grace judges her harshly, viewing her as unintelligent and unevolved. However, Kelly pays close attention to the prison environment and gathers information quietly.

Harry is an observant man who grew up in an aristocratic household before experiencing financial instability. He develops an intense fascination with Simon Artemis and the broader Artemis family. He closely monitors Grace's activities around London while keeping his own motives strictly hidden.

Marie is Grace's late mother. She immigrated to England from France to pursue modeling and became swept up in the nightclub scene, where she met Simon Artemis. She raised Grace in poverty after Simon and her own family rejected her, bearing the hardship with a quiet resilience that Grace often interprets as weakness.

Jeremy is Simon's father and the patriarch of the Artemis family. Originally from a working-class background, he aggressively masks his roots with exclusive club memberships and a carefully cultivated accent. He prioritized the family's wealth over basic morality, encouraging Simon to abandon his pregnant girlfriend.

Kathleen is Simon's mother, characterized by her obvious cosmetic procedures and perpetually dissatisfied expression. She is deeply prejudiced and fully supported her husband in ensuring Simon offered no financial help to Marie.

Andrew is the son of Lee and Lara Artemis. Rejecting the affluent and toxic environment of his extended family, he adopts a bohemian lifestyle and dedicates his time to environmental causes. He experiments with exotic frog toxins to treat depression.

Lee is Simon's younger brother, who lacks Simon's immense success and relies on a permanent chauffeur due to multiple drunk driving arrests. He frequently engages the services of sex workers and harbors specific kinks that make him vulnerable.

Lara is Lee's wife and Andrew's mother. She has spent years enabling her husband's destructive behavior but ultimately harbors a deep, realistic resentment toward his cruelty and selfishness.

Janine is Simon's wife, living in a heavily modernized, internet-connected home in Monaco. She enjoys the extreme luxury provided by her husband's business empire while remaining entirely isolated from the rest of the world within her high-tech environment.

Bryony is Simon and Janine's daughter. She operates as a superficial social-media influencer, entirely dependent on her family's fortune rather than any personal skills. She has a documented peach allergy that she routinely broadcasts to her internet followers.

Caroline is Jimmy's beautiful and highly privileged fiancée, born to a famous author and a former foreign secretary. She struggles with substance misuse and commands her romantic relationship with Jimmy through emotional outbursts. Her accidental, fatal fall off a balcony results in Grace's imprisonment.

Helene is Marie's only loyal friend during their difficult years in London. After Marie's death from cancer, Helene briefly takes a teenage Grace into her home and later inadvertently provides Grace with crucial information about the Artemis family's cruelty.

Sophie is Jimmy's mother. She provided Grace with formative reading material during her teenage years and later expresses concern over Grace's intense reaction to Jimmy's romantic relationships.

George is Grace's lawyer, diligently working to overturn her murder conviction. He remains confident that he can secure her release by finding evidence of her innocence regarding Caroline's death.

Amir works in the nightclub industry in Marbella. He is easily charmed by Grace, who flirts with him specifically to borrow his vehicle for her own secretive purposes without drawing attention.

Charlotte is Harry's mother. In her youth, she met Simon Artemis at a nightclub and had a brief romance with him, leading to a pregnancy that Simon ignored. She subsequently married another man who raised her child.

Christopher was the man who married Charlotte and raised Harry. He provided Harry with a stable, cultured upbringing, and his death prompts Harry to seek out the wealthy man who originally fathered him.

Pete is a seventeen-year-old hacker from Iowa. He possesses extensive knowledge of smart-home technology and is easily manipulated into remotely controlling devices in Monaco from across the world.

Lacey is a maid employed in Janine Artemis's household. Dissatisfied with her employer, she is persuaded to plug an external device into the home's internet hub under the guise of helping an investigative journalist.