Toby is an attractive, previously carefree public relations executive whose life derails after a brutal home invasion. The attack leaves him with lasting physical injuries and severe post-traumatic stress disorder. Accustomed to a lifetime of privilege and good fortune, he struggles to adapt to his new reality and moves into his family's ancestral estate, Ivy House, seeking stability.

Hugo is Toby's compassionate and observant uncle, a genealogist who uncovers family histories for his clients. Diagnosed with terminal brain cancer, he remains at the ancestral estate of Ivy House, tending to its garden and providing a safe haven for his nephew. He values family loyalty above all else.

Rafferty is a determined and pragmatic detective assigned to investigate the human remains found in the wych elm at Ivy House. He employs aggressive and sometimes questionable interviewing tactics, establishing an adversarial dynamic with Toby. Rafferty represents an authority figure who refuses to handle the privileged Hennessy family delicately.

Susanna is Toby's clever, fiercely protective cousin and the mother of Zach and Sallie. Having experienced personal hardships and injustices, she possesses a cautious worldview that often clashes with Toby's privileged perspective. She is deeply loyal to her family and actively advocates for Hugo's medical care.

Leon is Toby's cousin, an introverted man who has built a life for himself in Berlin. He shares a complex bond with Toby and Susanna, shaped by childhood summers spent at Ivy House. Haunted by memories of being severely bullied during his adolescence, Leon views the world with a heightened sensitivity to suffering.

Melissa is Toby's empathetic and practical girlfriend. Having grown up with a neglectful mother, she naturally adopts a caretaker role, prioritizing the well-being of those around her. She temporarily relocates to Ivy House to support both Toby's recovery from trauma and Hugo's battle with cancer.

Dominic is Toby's former secondary school peer whose life seemingly ended years ago. Remembered by Toby as a popular athlete, others in his social circle recall him as a cruel bully. The discovery of his skeleton on the Hennessy property brings long-buried adolescent tensions to the surface.

Declan, often called Dec, is one of Toby's childhood friends. Coming from a less privileged background than Toby, he is quick to call out Toby's arrogance and lack of empathy, serving as a critical voice regarding Toby's past and present behavior.

Sean is another of Toby's long-time friends. Unlike Dec, Sean tends to enable Toby's worldview, viewing his privileged ability to escape consequences with amusement rather than judgment.

Tiernan is Toby's former colleague at the art gallery. He loses his job after orchestrating a fraudulent marketing scheme using an invented persona named "Gouger," a scheme Toby knew about but failed to report to his superiors.

Detective Martin is one of the officers assigned to investigate the brutal attack at Toby's apartment. He treats Toby with a straightforward professionalism that Toby initially appreciates, though their lack of progress frustrates Toby as the months drag on.

Detective Bannon partners with Detective Martin to solve Toby's home invasion case. Together, they attempt to determine whether the attack was a random robbery or a targeted assault.

Toby's mother provides consistent support during his recovery and maintains a close bond with her brother Hugo. She frequently visits Ivy House to help with the garden and check on her son's well-being.

Tom is Susanna's husband and the father of Zach and Sallie. Viewed by Toby as somewhat dull and overly responsible, he provides a stabilizing contrast to the tightly knit, historically complicated Hennessy cousins.

Zach is Susanna and Tom's young son. His inquisitive and sometimes disruptive behavior leads to the discovery of a human skull hidden inside the trunk of an old wych elm tree on the property.

Sallie is Susanna and Tom's young daughter. She plays in the sprawling garden at Ivy House during family gatherings and is questioned by detectives alongside her brother.