A forensic psychologist and sleep expert working at the Abbey Sleep Clinic in London. He specializes in resignation syndrome and believes the mind is more powerful than the brain. Divorced and struggling with feelings of failure, he views his challenging new patient as a chance to prove his theories and repair his stagnant career.

A 29-year-old former journalist dubbed "Sleeping Beauty" by the media. Four years ago, she allegedly stabbed her two best friends to death while sleepwalking and subsequently fell into a deep, resignation syndrome-induced sleep. Before the incident, she was a driven, true-crime-obsessed writer who suffered from severe insomnia and parasomnia.

The Director of Central Intelligence and Ben's ex-wife. She was the first police officer on the scene of Anna Ogilvy's alleged murders four years prior. She is highly competent and protective of her daughter, viewing Anna solely as a criminal who needs to face the justice system.

Ben and Clara's young daughter. She lives primarily with her mother and occasionally struggles with anxiety related to the frightening aspects of her parents' law enforcement and psychological work.

Ben's boss and mentor at the Abbey Sleep Clinic. As an older, experienced professional, she handles high-end clients and coordinates the intense secrecy surrounding Anna's arrival. She has a history of working at Broadmoor Hospital.

The Deputy Director at the Ministry of Justice. He is a strict, commanding government official tasked with ensuring Anna Ogilvy wakes up to stand trial. He enforces intense confidentiality rules and monitors the media storm surrounding the case.

Anna Ogilvy's dedicated nurse. She manages Anna's physical needs and daily monitoring, eventually assisting Ben with his sensory stimulation therapies. She maintains a friendly, professional demeanor while dealing with the intense pressure of the assignment.

Anna's mother, formerly a high-profile politician with a focus on health, who reinvented herself as a humble church minister following the scandal of the murders. She carries immense guilt over ignoring her daughter's early sleepwalking episodes to protect her career.

Anna's wealthy father and a financial manager. He presents an upbeat, charismatic exterior but avoids discussing the deeper emotional realities of his daughter's condition and the tragic night at the Farm.

Anna's brother, who attended the fateful wilderness retreat where the murders occurred. He serves as a peripheral family member impacted by the media storm.

Anna's close friend and former roommate. He co-founded the true-crime magazine Elementary alongside Anna and Indira before being fatally stabbed in a cabin during a wilderness retreat.

A beautiful, ambitious young woman who co-founded Elementary magazine. She was one of Anna's closest friends before being murdered at the wilderness retreat.

An obsessive true-crime blogger who operates under the handle @Suspect8. She was present at the Farm on the night of the murders and considers herself an armchair sleuth uniquely qualified to solve the case.

An anonymous, intellectual psychiatric patient treated by Professor Bloom two decades ago. As a teenager, they exhibited vengeful tendencies and a deep fascination with power following a family tragedy.

A Broadmoor Hospital patient from 1999 who allegedly murdered her stepsons while sleepwalking. Her highly publicized case deeply fascinated Anna, who intended to write a book about her.