Cormoran is a 35-year-old war veteran turned private investigator operating out of London. Having lost his right leg in an explosion in Afghanistan, he struggles with physical discomfort and deep financial debt. Following a volatile breakup, he lives out of his office on a camp bed. He possesses a methodical mind and a gruff exterior, masking the deep emotional trauma of his upbringing and military service.

Robin is a highly capable young woman from Yorkshire who has just accepted a marriage proposal from her longtime boyfriend. Despite having no formal background in investigation, she harbors a lifelong, secret desire to do detective work. She quickly proves herself indispensable to the agency through her sharp intellect, pleasant demeanor, and proactive research skills.

John is a wealthy lawyer and the adoptive brother of the late model Lula Landry. Dissatisfied with the official police ruling of suicide, he insists on uncovering the truth behind his sister's fatal fall. He previously knew Cormoran during their childhood, using this past connection to secure the investigator's services.

Lula was a wildly famous and beautiful young model known affectionately to her friends as "Cuckoo." Adopted by a wealthy white family as a child, she spent her final months grappling with intense media scrutiny, mental health concerns, and a desperate desire to connect with her biological roots. Her fatal plunge from a balcony drives the central investigation.

Charlotte is Cormoran's beautiful, wealthy, and highly turbulent ex-fiancée. Their relationship involves years of breaking up and reconciling, but her recent actions push Cormoran to leave her apartment permanently.

Matthew is Robin's practical, financially minded fiancé. He disapproves of Robin's fascination with private investigation, viewing Cormoran as unprofessional and urging Robin to accept a standard corporate job.

Evan is a musician and Lula's on-again, off-again boyfriend. He has a highly publicized struggle with substance use and frequently argued with Lula in public, making him an early subject of police interest.

Guy is a highly successful fashion designer working in London. He viewed Lula as a muse and sister figure, remaining fiercely protective of her while harboring deep suspicions about the people who tried to use her for money.

Rochelle is a young woman who bonded with Lula during an outpatient psychiatric program. Operating on the fringes of Lula's glamorous life, she frequently accompanied the model on shopping trips and holds insights into Lula's final hours.

Tansy is a wealthy resident of Lula's building who claims to have overheard a vicious argument leading up to Lula's fall. The police dismiss her testimony entirely, attributing her claims to cocaine use.

Freddie is an aggressive film producer who resides in the apartment below Lula. He has a notorious temper, a history of harassing employees, and refuses to cooperate with outside inquiries.

Eric is a detective sergeant with the Metropolitan Police who worked on Lula's case. He is pragmatic and willing to quietly trade information with Cormoran outside of official channels.

Roy is a gruff, dismissive Detective Inspector who firmly believes Lula's death was a straightforward suicide. He resents any civilian interference in police matters.

Derrick is the security guard working the reception desk at Lula's luxury apartment building. He was absent from his post due to illness during a crucial window of time on the night in question.

Kieran is Lula's personal chauffeur and an aspiring actor. He felt a strong bond with Lula over their shared mixed-race heritage and feels ignored by the official police investigation.

Yvette is the matriarch of the Bristow family, currently suffering from terminal cancer. She adopted John, Charlie, and Lula, though her distant parenting style caused lifelong rifts within the family.

Tony is John and Lula's wealthy uncle and a successful lawyer. He is highly critical of the Bristow family dynamics and fiercely dismisses the idea that Lula was murdered.

Ciara is a beautiful, vivacious fellow model who spent part of the afternoon with Lula on the day she died. She introduces Cormoran to the exclusive nightlife scene Lula frequented.

Deeby is an American rapper who was scheduled to stay in the apartment below Lula's on the night of her death. He frequently receives free promotional clothing from Guy Somé.

Charlie is the Bristow family's eldest adopted son who died tragically in childhood. His death casts a long shadow over the family and influenced their decision to adopt Lula.

Lucy is Cormoran's younger half-sister. Having survived the same chaotic upbringing, she craves suburban normalcy and worries constantly about Cormoran's messy lifestyle and physical well-being.