Marissa is a highly successful solicitor managing financial estates in the affluent suburb of Kerryglen. Married to a wealth manager, she enjoys a life of extreme privilege, living in a stately Edwardian home called Maple Lodge. Her seemingly perfect life shatters when her four-year-old son goes missing, forcing her to rely on her own inner strength to uncover the truth.

Jenny is a driven businesswoman who recently earned a promotion that makes her the primary earner in her family. She constantly feels inadequate trying to balance her career with raising her young son. When her nanny absconds with Marissa's child, Jenny experiences intense guilt over having vetted and hired the woman.

Carrie is a seemingly timid, unassuming nanny hired by the Kennedy family. She initially presents herself as a quiet girl from County Wicklow with a tragic but respectable background. In reality, she uses her position within the Kennedy household to orchestrate the kidnapping of Marissa's son.

Irene is a woman who escaped a turbulent, working-class past to marry into middle-class comfort. She has been estranged from her daughter for nine years and prioritizes her own status over her family ties. She views the high-profile kidnapping case primarily as an opportunity to gain attention and money by selling her story to tabloids.

Peter is a confident wealth manager who comes from a family of significant means. He projects the image of a perfect, protective husband who takes charge of the search efforts for his son. Accustomed to having power in any room, he expects others—especially his younger brother—to follow his orders without question.

Colin is a solicitor and Marissa's business partner of twenty years. He presents himself as a bumbling, well-meaning professional who relies on charm to smooth over his clumsiness. He assists Marissa by managing their firm's financial matters during her absence.

Milo is the four-year-old son of Marissa and Peter. He attends Kerryglen National School and has synesthesia, a condition that causes him to associate words and numbers with specific colors. His abduction from a fake playdate sets the entire investigation in motion.

Richie is a schoolteacher married to Jenny. He frequently exhibits traditional expectations regarding domestic labor, expecting his wife to manage childcare despite her demanding career. He often sides with his mother's conservative views, creating friction in his marriage.

Brian is Peter's younger brother, who lives in a smaller cottage on the Maple Lodge estate. He generally acts as an assistant to his older brother, running errands and taking orders without complaint.

Adeline is Richie's conservative, overbearing mother. She holds highly traditional views on motherhood and openly criticizes Jenny for employing a nanny instead of staying home full-time.

Ana is the young Brazilian au pair employed by the Irvine family. She cares deeply for Milo but maintains a quiet profile due to her anxiety regarding her immigration status and a general distrust of the police.

Detective McConville is an investigator with the gardaí (Irish police). She serves as the primary liaison for the Irvine family, coordinating the search efforts and updating the parents on new leads.

Esther is an elderly woman and former foster mother who lives in suburban Dublin. She inadvertently becomes involved in the case when the kidnapper uses her address to trick Marissa.

Jacob is the young son of Jenny and Richie Kennedy. He is a student at Kerryglen National School and is cared for by Carrie, who uses her access to him to gain proximity to her actual target.

Kyle is Carrie's boyfriend, possessing a lengthy criminal record. His presence near the Kennedy home raises alarms during the investigation into Carrie's background.

Rob is a career criminal and Carrie's absentee father. He abandoned his family when Carrie was young but reenters the narrative through his daughter's criminal plans.

Lia is Peter and Brian's carefree sister who lives in New York. She provides Marissa with a brief respite from the tension of the investigation, offering a detached perspective on the suburban drama.

Frank is a respectable, middle-class bank employee married to Irene. He is deeply concerned with appearances and worries primarily about how his wife's connection to a kidnapping case will affect his professional reputation.

Mark is Jenny's colleague at work. He provides professional support when she is distracted by the kidnapping and occasionally flirts with her, which introduces minor complications to her home life.