Cathy is a veterinarian and the middle sibling of the Plant family. She carries deep-seated guilt stemming from a childhood tragedy, which pushes her to act as the responsible conscience of her family. When Frannie hits a man with her rented Land Rover, Cathy's immediate instinct is to take charge and help. Her clinical training allows her to assess the grim situation objectively, but she quickly finds herself trapped in a nightmare of lies.

Joe is a veterinary surgeon and the fiercely protective older brother to Cathy and Frannie. Haunted by the childhood loss of their sister Rosie, he assumes the role of the family patriarch. He tries to manage the crisis in Italy with a misdirected sense of confidence, planning the cover-up to shield his youngest sister from prison. His intense anxiety and volatile temper cause his control over the situation to rapidly deteriorate.

Frannie is the youngest of the Plant siblings and the mother of a young boy named Paul. Her older siblings view her as the fragile baby of the family, a perception she leans into when she hits a man with her car. Terrified of going to prison and losing her son, she begs Joe and Cathy to help her hide the body instead of calling for an ambulance.

Lydia is Joe's wife and works as a secretary at a criminal law firm. She comes from a traumatic family background and has a deep desire to build a stable life, specifically hoping to conceive a child with Joe. Her difficult past makes her hyper-vigilant to dishonesty, leading her to quickly realize that Joe and his sisters are hiding a massive secret.

Evan is a veterinary colleague of Joe and Cathy who is struggling financially following a bitter divorce. He works a second job as a delivery driver to make ends meet. When he accidentally overhears the siblings discussing the hidden body, he senses an opportunity and demands a partnership in the practice in exchange for his silence.

Tom is a divorced man whom Cathy meets by chance at the airport. His easygoing, lighthearted nature provides a sharp contrast to the suffocating tension of the Plant family. He offers Cathy a safe space to exist outside of her criminal complicity and gently encourages her to prioritize her own moral well-being.

William is a half-British Italian police officer. Frannie hits him with her rented vehicle, triggering the siblings' frantic cover-up. The discovery of his wallet and a blood-stained document in his pocket escalates the family's fear that they are the targets of an active police investigation.

Maria is the mother of Joe, Cathy, and Frannie. Following the sudden death of her youngest daughter decades earlier, she became highly anxious and controlling. She remains heavily involved in the family's veterinary practice but is kept completely in the dark regarding her children's crimes.

Owen is the emotionally repressed father of the Plant siblings. The traumatic loss of his daughter Rosie caused him to withdraw emotionally from his surviving children, forcing them to rely exclusively on one another for support and protection.

Jason is a professional consultant whom Cathy meets with in the present-day timeline. He listens to her formal account of the escalating crimes and offers strategic advice as the legal realities of the family's cover-up finally catch up with them.

Paul is Frannie's young son. He is the central motivation for Frannie's desperation to avoid prison, as she cannot bear the thought of abandoning him.

Rosie is the Plant siblings' deceased sister who died of sudden infant death syndrome decades ago. Her loss fundamentally broke the family dynamic, instilling Cathy with lifelong guilt and turning Joe into a frantic protector.

Matteo is an Italian prosecutor who questions Joe and Cathy regarding the disappearance of William McGovern. His sharp, methodical interrogation tactics immediately expose the logical flaws in the siblings' hastily constructed alibis.

Carina is the Plants' neighbor in Verona. She unknowingly delivers catastrophic news when she casually informs Joe that the woods where they buried the body are scheduled for imminent property development.