Adrian is a charming architect who prides himself on maintaining an amicably blended family across his three marriages. He relies on a whiteboard called the "Board of Harmony" to schedule his interactions with his five children and two ex-wives. Averse to conflict, he prefers to focus on new beginnings rather than confront the emotional fallout of his past divorces. Following his wife's passing, he attempts to quickly rehome her cat to avoid painful reminders of his loss.

Adrian's third wife is a young woman struggling to find her place within his sprawling, pre-existing family. Having been bullied in her youth, she possesses an intense need to please those around her and often suppresses her own desires to keep the peace. She feels isolated within her marriage and hopes that having a baby will solidify her position in the household. Throughout her time with Adrian, she quietly endures cruel, anonymous emails without seeking his help.

Adrian's eldest daughter works as a nanny for her younger half-siblings. She remains fiercely protective of her mother, Susie, and carries deep resentment toward anyone she views as a threat to her family's stability. She masks her internal anger with a friendly, supportive exterior while secretly turning to stress-eating to cope with her father's repeated departures.

Adrian and Susie's 23-year-old son lacks direction and struggles to establish a career. He uses a cynical, sarcastic demeanor to shield himself from feelings of abandonment stemming from his parents' divorce. Despite his hostile exterior, he acts as a direct communicator who challenges his father's idealized version of their family dynamic. He forms a quiet understanding with Maya during a family holiday.

Adrian and Caroline's middle son is a secretive pre-teen who frequently retreats into digital spaces. He struggles to process his parents' separation and occasionally skips school to sit alone at a local train station. He carries a heavy sense of guilt regarding Maya's death and resents his father's attempts to manage their relationship through structured schedules.

Adrian's second wife acts as the pragmatic matriarch for her household. She maintains a composed, stoic exterior to ensure stability for her children following her divorce. She actively pursues new relationships and personal fulfillment, refusing to let her ex-husband's departure dictate her future.

Abby works with and shares an apartment with Jonathan Baxter's son, Matthew. She possesses distinctive mismatched eyes, one blue and one a mix of blue and amber. As an impartial observer of the Wolfe family's tragedy, she holds crucial details about Maya's emotional state on the night of her death.

Adrian and Caroline's daughter is an emotionally reserved child who dedicates her energy to competitive ice skating. She perceives her father as a "love addict" and openly doubts his ability to keep his promises.

Adrian and Caroline's youngest son is a toddler who has no clear memories of his parents living together. He frequently asks his father simple, direct questions about when he will move back home.

Adrian's first wife and the mother of Cat and Luke. She embraces a scruffy, relaxed lifestyle in her home in Hove and maintains an amicable, friendly relationship with her ex-husband.

Luke's ex-girlfriend who actively attempts to rekindle their romance. She views Maya as a rival for Luke's attention and frequently delivers passive-aggressive comments disguised as sympathy.

Caroline's boyfriend who integrates himself into her household. He offers to help the younger children with their homework and represents Caroline's willingness to move forward with her life.

A police detective who investigates the circumstances of Maya's death. He listens skeptically to Adrian's claims about his perfectly amicable blended family.

A police detective who agrees to look into the cyber-bullying directed at Maya. He manages Adrian's expectations regarding the likelihood of tracing anonymous digital messages.

The manager at an estate agency who provides Adrian with a crucial lead regarding his son Matthew's roommate.

Jonathan Baxter's son who works and lives alongside Abby.

One of Maya's friends who provides a rare outlet for Maya to express her misery regarding her failing marriage.

Maya's pet cat. The animal initially serves as a painful reminder of Adrian's loss, prompting him to try and rehome her. The cat resists Adrian's early attempts at affection, forcing him to accept that he cannot easily control his grief.