Family anchor under pressure. Lia Irvine is introduced as the younger sister of Peter Irvine and older sister to Brian Irvine. From the moment her nephew’s disappearance shocks the family, Lia is physically and emotionally present — part of the initial shock, part of the search, part of the family’s public face.

Haunted past, immediate suspicion. Lia is a recovering drug addict, which taints how others perceive her when the crisis begins. Her history and vulnerability make her an easy — and believable — target for suspicion, especially as secrets start unraveling.

Moral complexity & shifting loyalties. As the truth begins to emerge — about the kidnapping, the former car crash, and hidden baby-switching — Lia is caught between protecting her brother and acknowledging the terrifying possibility that he may be guilty of far worse than negligence. Her loyalty and love clash with her conscience, forcing a nuanced inner conflict.

Support and fragility — a mirror to the family’s collapse. Lia’s emotional fragility, guilt (from her past) and deep familial bonds add human weight to the series’ unfolding horror. She reflects the collapse of trust, the burden of shared secrets, and the destructive power of lies — not just for others, but for oneself.

Symbol of truth’s cost. In a story built on deception — fake identities, switched babies, betrayals — Lia represents what’s at stake when truth surfaces: not safety, but chaos. Her arc reminds the audience that even well-meaning love and loyalty can be corrupted by secrets.