Rob is a 31-year-old detective with the elite Dublin Murder Squad. As a child named Adam, he survived a traumatic incident in the Knocknaree woods where his two best friends vanished. He now conceals his past from his superiors while working a new murder case in the exact same location. He dresses impeccably in tailored suits and struggles with fragmented memories of his youth that surface during the investigation.

Cassie is a 28-year-old detective and Rob's dedicated partner on the force. She defies department dress codes by wearing cargo pants and pullovers, contrasting with Rob's formal attire. Her studio flat serves as the central gathering place for their case discussions. She possesses strong profiling skills developed during her time studying psychology in college.

Sam is a 35-year-old rookie detective assigned to investigate the motorway angle of the Katy Devlin case. He has valuable political connections through his family, making him a specific asset to the Murder Squad. He quickly forms a tight-knit trio with Rob and Cassie, sharing meals and analyzing evidence in the evenings.

Rosalind is Katy and Jessica's older teenage sister. She dresses sophisticatedly and appears oddly out of place in her grieving, chaotic household. She quickly singles Rob out for attention, claiming he is the only one who can solve her sister's murder. Her apparent fragility sparks a protective instinct in the male detectives.

Damien is a college student working at the Knocknaree archaeological dig. He has a boyish appearance with short brown curls and a sweet, eager-to-please personality. He provides early witness statements to the detectives regarding suspicious activity near the crime scene and cooperates fully with the police presence at his workplace.

Katy is a 12-year-old girl from the Knocknaree estate whose murder drives the main investigation. She is a dedicated and talented ballet prodigy who has recently been accepted into the Royal Ballet School. Her unexplained death disrupts the community and forces investigators to examine her family's history.

Jonathan is Katy's father and the spearhead of the Move the Motorway protest group. He grew up in the Knocknaree area as part of a close-knit group of bikers. He faces intense police scrutiny when detectives discover his childhood connections to the woods where the 1984 disappearances occurred.

Margaret is Katy's grieving mother. She lives in the Knocknaree estate with her family and struggles immensely to cope with the sudden loss of her middle child, rendering her largely unable to assist detectives.

Jessica is Katy's 12-year-old twin sister. She exhibits signs of autism and struggles to communicate clearly with investigators. She provides fragmented but potentially crucial details about the days leading up to Katy's death.

O'Kelly is the pragmatic boss of the Dublin Murder Squad. He demands quick results and expects his detectives to adhere strictly to department protocols. He balances the pressure of solving high-profile crimes with the political realities of policing a major city.

Jamie is one of Rob's childhood best friends who vanished in the Knocknaree woods. She was a tomboy who dreaded being sent away to boarding school. Her disappearance continues to haunt Rob decades later.

Peter is Rob's other childhood friend who disappeared alongside Jamie. He was the natural leader of their small trio, possessing a confident and commanding presence among his peers.

Mark is the supervisor of the archaeological dig. He is intensely passionate about salvaging Bronze Age artifacts before the new motorway destroys the area. He views the site with quasi-religious reverence, which initially draws police suspicion.

Mel is a worker at the archaeological dig. She provides the detectives with information regarding the local teenagers who frequent the site and serves as an alibi for her supervisor.

Dr. Hunt is the director of the archaeological dig site in Knocknaree. He manages the excavation process and controls access to the secure sheds where artifacts are stored.

Simone is the head of the ballet school where Katy studied. She recognizes Katy's exceptional talent and helped organize fundraisers to pay for the girl's advanced training at a prestigious academy.

Vera is the maternal aunt of Katy, Jessica, and Rosalind. She provides a secondary home for the girls, inadvertently creating an alibi for family members on the night of the murder.

Sandra is a local Knocknaree resident who was involved in a disturbing incident with Jonathan Devlin and his friends when they were teenagers. She dismisses the gravity of the past event, complicating the detectives' working theories.

Cathal is an old childhood friend of Jonathan Devlin. As teenagers, they formed a tight-knit biker trio that frequented the Knocknaree woods.

Shane is the third member of Jonathan Devlin's teenage biker trio. He participated in their group activities in the woods and provides silent resistance when questioned by police in the present day.

Terence is a local businessman facing financial trouble. He becomes a prime suspect in the harassment campaign against the Move the Motorway protest group, drawing police attention to local land deals.

Redmond is Sam O'Neill's uncle and a powerful local political figure. He presents a respectable public face but maintains quiet involvement in lucrative property development deals around the proposed motorway.

Heather is Rob Ryan's roommate. They share a living space but maintain a distant relationship, with Rob actively avoiding her emotionally draining presence by sleeping on Cassie's couch.

Kiernan is one of the original detectives who worked the missing persons case when Peter and Jamie vanished. He maintains a steadfast theory about what happened in the woods and remains convinced the children never left Knocknaree.

McCabe partnered with Kiernan during the 1984 investigation into the missing Knocknaree children. He held differing theories from his partner, suspecting a transient individual dragged the children away.

Sean is a worker at the Knocknaree archaeological dig. His misplaced trowel, marked with his initials, provides a crucial piece of physical evidence for the detectives investigating the murder scene.