Amber is a 30-something assistant host for a highly rated BBC radio morning show. Trapped in a coma after a severe car accident, she is entirely aware of her surroundings but unable to communicate. She admits from the very beginning that she is a compulsive liar. Helpless in her hospital bed, she uses snippets of bedside conversations to piece together her fractured memories of the days leading up to the crash and her failing marriage.

Claire is Amber's younger adopted sister, though they first met as 10-year-old schoolmates. Through 1991 diary entries, she is introduced as a lonely child adjusting to a new school and a turbulent home life. As an adult, Claire is deeply embedded in Amber's life and seemingly favored by their parents. She demands loyalty and maintains a fiercely protective, sometimes overbearing presence in Amber's daily routine.

Paul is Amber's husband and a recently successful novelist. He spends much of his time in a backyard shed writing, a habit that has caused him to grow emotionally distant from his wife since the publication of his first book. Following Amber's car crash, his evasive answers to police questions and his unexplained absences prior to the accident cast a shadow of suspicion over his actions.

Edward is Amber's ex-boyfriend from a decade ago who now works as a low-level orderly at a hospital near her home. Once a promising medical student, he lost his career prospects following a series of sexual harassment accusations. He retains his handsome charm and reconnects with Amber just as her marriage is faltering, though he still harbors lingering resentment over his derailed past.

Madeline is the famous and dictatorial principal host of a popular BBC morning radio show. She is openly condescending to her staff and creates a high-pressure environment at the studio. Unaware of the resentment brewing among her subordinates, she becomes the target of an elaborate plot engineered to destroy her career.

Jo is Amber's closest friend and confidant at the radio studio. Kind and consistently supportive, Jo is the only person at work whom Amber feels she can truly rely on. She helps Amber survive the stressful workplace politics of the *Morning Coffee* show and actively assists in the scheme against their boss.