Paul is a former Gritten resident who works as an English teacher. He returns to his hometown after an absence spanning twenty-five years. A brutal murder from his teenage years casts a long shadow over his life, causing him to avoid his past and isolate himself socially. His initial instinct upon returning is to fulfill his familial duties and leave quickly, but strange occurrences and his mother's cryptic warnings pull him back into old mysteries.

Amanda is a police detective assigned to a high-profile murder case involving two teenage suspects. She relies heavily on her empathy and intuition, though she worries these traits make her vulnerable. Following the recent death of her father, a former police officer who preached emotional detachment, she attempts to find a balance between professional objectivity and human compassion. Her investigation forces her to confront an online true-crime subculture fixated on an old case.

Charlie is an enigmatic teenager from Paul's past who serves as the architect of the original Gritten tragedy. He possesses a calm, unnerving charisma that allows him to exert significant influence over isolated and insecure classmates. By introducing his peers to lucid dreaming, he presents fantasy as a tool for gaining power and control. His disappearance after a horrific crime elevates him to a mythological status among online communities.

James is a timid and defenseless boy in Paul's youth who desperately seeks protection and acceptance. Initially relying on Paul to shield him from bullies, he finds a more intoxicating form of security in Charlie Crabtree's promises. James's vulnerability makes him the ideal subject for Charlie's psychological experiments, leading him into a dangerous obsession with lucid dreaming and dream diaries.

Billy is a sullen, easily led teenager who serves as Charlie Crabtree's enforcer. He is drawn to the violence that Charlie's leadership enables, happily participating in the group's hierarchy. He is obsessed with weapons like knives and slingshots. Following his role in the original Gritten murder, he spends twenty years in prison before returning to his family home on parole.

Carl is James Dawson's stepfather. He is characterized as a kind, humble, and gentle man who attempts to provide a stable environment for his family. He eventually moves away from Gritten to the town of Brenfield with his wife, putting distance between his family and the site of the traumatic events.

Daphne is Paul's mother, a lifelong resident of Gritten whose recent fall down the stairs places her in hospice care. Suffering from terminal cancer and dementia, her mental decline causes her to voice fragmented, terrified warnings about the past. She spends her final days trapped by memories she spent decades trying to suppress for her son's sake.

Dean is the devastated father of Michael Price, the teenager killed in the recent Featherbank copycat murder. A former soldier, he is consumed by grief and anger over the loss of his child. His military background provides him with a specific set of skills, and his inability to accept the tragedy drives his actions in the present day.

Jenny is an intelligent and kind teenage girl from Paul's past. She stands out as a beacon of normalcy in the grim environment of Gritten, sharing Paul's interest in writing and storytelling. She even manages to publish a short story in a horror anthology called The Nightmare People. Her presence in Paul's memories offers a sharp contrast to the toxic dynamics of his other friendships.

Michael is a teenage boy from Featherbank whose brutal murder sets the present-day plot in motion. His body is found posed in a ritualistic manner surrounded by bloody handprints, directly mirroring the infamous crime committed in Gritten twenty-five years earlier.

Elliot is one of the two teenagers responsible for the present-day copycat murder in Featherbank. He is heavily involved in online true-crime forums and keeps a dream diary, attempting to replicate the methods of the notorious Charlie Crabtree.

Robbie is the second teenager involved in the copycat killing in Featherbank. Like Elliot, he carries a dream diary and operates under the delusion that the murder will grant him access to a supernatural realm.

Eileen is James's mother and Carl's wife. She lives in a state of high anxiety, often exhibiting erratic behavior, such as frantically cleaning blood from her door in an attempt to maintain a veneer of normalcy in her home.

Marie owns Johnson & Ross, the local bookshop in Gritten. She is a repository of local history and legends, remaining a constant presence in the town over the twenty-five-year gap. She inadvertently inspires Jenny's writing by sharing folklore with her.

David is a school bully in Paul's youth who frequently targets the more vulnerable students. His accidental death, which Charlie Crabtree eerily predicts in a detailed dream, serves as the catalyst that solidifies Charlie's power over the other boys.

Mr. Goodbold is a teacher at Gritten Park who willfully overlooks the cruelty of his students. He becomes a target of Charlie Crabtree's group, who plot against him in their shared dream experiments.

Mary is the grieving mother of the recently murdered teenager Michael Price. The devastating loss shatters her world, and she becomes increasingly terrified by her husband Dean's erratic and obsessive behavior in the aftermath.

Sally is a dedicated care worker looking after Daphne Adams in her final days. She provides Paul with updates on his mother's fluctuating lucidity and the circumstances surrounding her admittance to the facility.

John is a detective who works alongside Amanda Beck. He assists in processing the initial grisly scene of the copycat murder.

Colin is Amanda Beck's superior officer. He is primarily concerned with the optics and swift closure of the investigation, pushing for an immediate resolution rather than digging into the complex history of the crime.

Theo is a tech analyst and cybercrime specialist. He plays a crucial role in the modern-day investigation by attempting to track the IP address of the anonymous forum user goading the teenage killers.

Owen is a local police officer in Gritten. He is largely dismissive of Paul's concerns regarding the strange occurrences around the Adams house, attributing them to pranks or Paul's grief.

Graham is a Gritten police detective who worked on the original Charlie Crabtree case twenty-five years ago. He is stubborn and quick to jump to conclusions, frequently clashing with Amanda over the direction of the new investigation.