Amelia Wright is an employee at the Battersea Dogs Home who won a weekend retreat to Blackwater Chapel in a raffle. Orphaned at birth and raised in the foster care system, she is highly protective of her relationships but increasingly anxious about her failing marriage. She views the isolated weekend getaway as a final attempt to reconnect with her emotionally distant husband.

Adam Wright is a successful screenwriter specializing in adapting obscure novels into films. He suffers from prosopagnosia, or face blindness, rendering him unable to recognize anyone, including his own wife, by their facial features. To cope with his condition and the pressures of the film industry, he often retreats into his isolated writing shed, emotionally distancing himself from those around him.

Robin Wright is a secretive, middle-aged recluse living entirely off the grid in a two-room cottage on the grounds of Blackwater Chapel. She closely monitors the weekend visitors and makes stealthy excursions into the chapel in the dead of night. Isolated and deeply familiar with the building's dark history, she harbors hidden motives regarding the couple's stay.

Henry Winter is an acclaimed, notoriously reclusive horror novelist whose works Adam passionately adapts. He is the enigmatic owner of Blackwater Chapel, having purchased the surrounding land to ensure his absolute isolation. Feared by many who cross his path, he is a demanding curmudgeon who exerts immense control over his literary empire.

Bob is an aging black Labrador retriever who accompanies Adam and Amelia on their weekend trip. Adopted from a shelter, he represents a rare point of shared history and affection in the couple's strained household.

October O'Brien is a stunningly beautiful, thirty-year-old A-list Hollywood actor. She takes a strong professional interest in Adam's original screenplay and integrates herself into his life, bringing both industry success and domestic tension.

Sam is a private investigator and an avid fan of Henry Winter's writing. He has successfully represented and aided the reclusive author for years, handling his private affairs and tracking information when Henry cuts off contact with the outside world.

Oscar is a white rabbit who lives in the secluded cottage on the grounds of Blackwater Chapel. He serves as Robin's sole living companion in her extreme isolation.

Adam's mother is a figure from his past who frequently wore a red kimono, especially when entertaining male visitors. Her tragic death in a hit-and-run accident when Adam was thirteen continues to haunt him into his adulthood, manifesting in vivid nightmares.

Robin's mother lived at Blackwater Chapel before her untimely death. She often sought refuge in the nearby two-room cottage to escape abuse, leaving a lasting impression on her daughter.

Patti is a clerk at the store closest to Blackwater Chapel. Like many locals in the remote Scottish Highlands, she harbors a strong distaste for the chapel's reclusive and intimidating owner.