Annie is a 25-year-old aspiring writer who recently inherited the sprawling Gravesdown estate and £40 million. She feels isolated in the village of Castle Knoll, where locals give her the cold shoulder because she possesses her great-aunt's extensive files on their private secrets. Restless but resourceful, she steps into the role of amateur sleuth when a mysterious fortune-teller directs her to investigate a 60-year-old fatal car crash.

Frances is Annie's late great-aunt and the former owner of Gravesdown Hall. In her youth during the 1960s, she is a sharp, fiercely determined young woman fixated on outsmarting a grim prophecy regarding her own death. She channels her anxieties into becoming a meticulous collector of the villagers' darkest secrets, creating a massive archive that serves as both a weapon and a shield.

Archie is Frances's former gardener who now runs a classic car restoration business in Castle Knoll. A charming and wry man with a deep knowledge of village lore, he harbors a long-standing resentment against the aristocratic Gravesdown family. In the 1960s timeline, he is an adventurous youth who partners with Frances to uncover the village's darkest truths.

Eric is Archie's brother and a mechanic working at the Foyle family's car restoration business. In the 1960s, he is a troubled youth who briefly works as a valet for the Gravesdowns and resents the rigid class hierarchies of Castle Knoll. He is fiercely protective of those he cares about and carries the weight of a lifetime of perceived injustices.

Peony is the enigmatic, elderly fortune-teller of Castle Knoll, known for her striking white hair and unusual green eyes. Born Ellen Jones, she reinvented herself after a youthful act of vigilante justice against the powerful Gravesdown family. Her cryptic prophecies dictate the actions of many villagers, though she possesses a deep personal history intertwined with the very mysteries she predicts.

Ford is the youngest Gravesdown son who inherited the family's vast wealth following a fatal car accident. He is a complex, manipulative figure who uses his aristocratic status to suppress scandals and protect the family name. Trapped between a desire for a respectable life and the dark secrets of his relatives, he wields his privilege to silence the less fortunate.

Birdy is a local girl connected to the Foyle brothers who disappeared years ago. Her life is heavily impacted by the predatory actions of the Gravesdown family, tying her fate to the tragic events of 1961. She harbors a fierce, misguided loyalty to those she believes have protected her from the village's corrupt elites.

Crane is a local police detective and an ally to Annie in Castle Knoll. He is competent, logical, and deeply dedicated to proper procedure, though he finds himself continually drawn into Annie's unconventional investigative methods. He clashes frequently with his new superior regarding the handling of local cases.

Samantha is the gatekeeping receptionist at the local police station. She possesses access to both official and unofficial information and has deep ties to the older generation of villagers, having been a part of Archie and Eric's social circle during the 1960s.

Edmund is the eldest son of the aristocratic Gravesdown family, known for driving a garish purple Bentley. He leverages his immense wealth and social standing to commit predatory acts against women with complete impunity. His behavior establishes a corrupt environment that breeds deep generational resentment among the working-class villagers.

Olivia is the aristocratic wife of Edmund Gravesdown who perishes alongside him in a 1961 car crash. Initially perceived by the village as a bystander to her husband's toxic behavior, her true role within the family's hierarchy reveals a fierce dedication to protecting their wealth and status at the expense of others.

Saxon is the adult son of Edmund and Olivia Gravesdown. Having lost his inheritance to Annie, he harbors a quiet bitterness but remains fixated on uncovering the truth behind his parents' violent deaths. He conducts his own private investigations into the family's dark legacy, serving as a cynical counterpoint to Annie.

Jenny is Annie's best friend from London, who works as a window display designer at Harrods. She provides a grounded, outside perspective on the eccentricities of Castle Knoll and loyally assists Annie in investigating the village's escalating mysteries, despite her clear unease with the eerie estate.

Marks is the newly appointed chief inspector at the Castle Knoll police station. He is a senior officer with deep roots in the community who rigidly adheres to procedure. He frequently clashes with Detective Crane over jurisdiction and views amateur sleuths with intense suspicion.

Beth is Archie Foyle's granddaughter, who runs the local deli and frequently delivers groceries to Gravesdown Hall. She lives with her wife Miyuki at the farmhouse and is highly protective of her grandfather's well-being and privacy.

Lord Harry is the patriarch of the wealthy Gravesdown family who died in the 1961 car accident. His legacy of aristocratic privilege and unchecked influence set the standard for his sons' behavior in the village.

Emily is Frances's best friend during the 1960s, whose sudden disappearance shatters Frances's sense of security. Her absence deeply impacts the lives of those left behind in Castle Knoll.

Miyuki is Beth's wife who resides at the Foyle family farm, helping to maintain their close-knit domestic life away from the village's prying eyes.

Elva is Saxon Gravesdown's wife, who shares her husband's resentment over losing the family inheritance to an outsider. She maintains a tense distance from the new owner of Gravesdown Hall.

Lucy is the former Castle Knoll librarian who was briefly married to Archie Foyle. Before falling terminally ill, she asked him to care for her young granddaughter, cementing his family ties.

Sam is a figure from Annie's family's past who recently re-enters the picture. His sudden reappearance following Annie's massive inheritance causes her intense suspicion regarding his motives.