Sally is a 42-year-old woman living an isolated life in the rural area of Carricksheedy. She interprets language very literally and avoids social interactions because the townspeople view her as odd. After her father's death thrusts her into the public eye, she inherits a series of letters detailing her early life. She sets out to integrate herself into the community while managing her extreme anger issues.

Angela is a doctor and a long-time family friend of the Diamonds. She steps in to manage the police investigation and the media attention surrounding the unusual disposal of Thomas's remains. She provides practical advice and ongoing emotional support to help smooth Sally's transition to independent living.

Thomas is a former psychiatrist who raised Sally alongside his wife, Jean, in a secluded rural home. He leaves behind letters that document his psychiatric observations and provide the missing context of Sally's childhood. His parenting choices prioritize isolation to protect his daughter, heavily influencing her adult behavior.

Mark is a man who relocates following a divorce. He carries deep psychological scars stemming from a severe family tragedy involving the childhood disappearance of his sister. He takes an intense interest in local residents and historical family records to process his grief.

Conor is a deeply misogynistic man who isolates his household from the outside world. He exerts total control over those in his physical space, employing strict rules, locked doors, and elaborate lies to maintain his authority. He relocates across the globe to continue living completely off the grid.

Peter is a boy raised entirely indoors by his father in extreme seclusion. His understanding of the outside world comes strictly from television and his father's manipulated narratives. He relies entirely on his father due to a supposed rare medical condition that prevents him from touching others.

Denise is a woman who was abducted at age eleven and held captive for over a decade. After her eventual rescue, she is institutionalized at St. Mary's Psychiatric Hospital under the care of Thomas Diamond. She struggles with severe trauma and exhibits a fierce, protective nature toward her offspring.

Jean is Thomas's late wife. During her life, she advocated for integrating her family more fully into society, though her views often clashed with her husband's protective, isolating approach. She maintained strong friendships with local women like Angela.

Christine provides crucial information about historical events when her family members need clarity. She collaborates frequently with local friends to ensure the safety and well-being of those she cares about, offering a grounded perspective on past tragedies.

Nadine shares her home with her wife and their two dogs. She offers a safe, stable place to stay when police search nearby residences, providing background support during community crises.

Abebi is a preteen girl who initially fears the residents of a secluded local house due to town rumors. As a Black child in a predominantly white Irish town, she understands what it feels like to be marginalized by the community, allowing her to form an unexpected bond with isolated neighbors.

Maduka shows early empathy toward outcasts, recognizing that he shares common ground with them as an outsider in Carricksheedy. He helps bridge the gap between his family and isolated members of the community.

Martha is a yoga studio owner. She welcomes isolated people into her social circle, introducing them to yoga as a tool for managing stress and inviting them to local gatherings.

Tina is a psychotherapist who helps clients work through anger management issues and post-traumatic stress. She provides actionable advice for navigating social conversations and building a healthy, independent lifestyle.

Caroline is the manager of the local Texaco shop. She harbors strong prejudices and directs racist and anti-gay bias toward several members of the community, frequently clashing with those who challenge her views.

Lindy is a fourteen-year-old girl who is abducted and locked in a soundproof barn. She spends years in captivity, making numerous unsuccessful escape attempts while dealing with her captors.

Rangi is a boy of Māori descent living in New Zealand. He bonds with his neighbor over feeling like an outsider and dealing with difficult family situations. He provides a brief, crucial window into normal adolescent friendship for a highly isolated boy.

Georgia cares for her nephew in New Zealand. When tragedy strikes, her concerns are dismissed by the local authorities due to systemic prejudice, leaving her without answers.

Sue is a woman of Indian descent who helps newcomers navigate social situations. She accompanies friends on shopping trips to Dublin and supports them through various community conflicts.

Amanda is a twenty-three-year-old musical composer and successful concert pianist. She focuses intensely on her career and seeks to build a healthy identity separate from the difficult stories surrounding her adoption. She receives a worn teddy bear in the mail, viewing it as a simple lucky charm.

Kate is a podcaster who investigates true crime stories. She digs into decades-old disappearances and attempts to contact various individuals connected to these cold cases, seeking interviews for her show.

Ger runs a cattle farm bordering a secluded property. He represents the local community's curiosity and occasional intrusion into isolated lives, later benefiting from local land sales.

Geoff is a solicitor hired to handle criminal defense issues. He successfully negotiates legal trouble to get charges dropped regarding improper conduct, providing crucial legal shielding.