Rachel is a freelance photographer and former nurse living in Bristol. Recently divorced from her husband, she struggles with the demands of single motherhood and constantly second-guesses her parenting decisions. When her eight-year-old son vanishes during a walk in Leigh Woods, her outward displays of raw panic and despair cause the media and public to view her as unstable and potentially dangerous.

Benjamin, known as Ben, is an eight-year-old boy with blond hair, blue eyes, and freckles. Before his sudden disappearance, he demonstrates an open, trusting nature, though he previously required emotional support from his teacher to cope with his parents' divorce. He secretly carries a security blanket called "nunny" and enjoys playing online video games.

Jim is a tall, dark-haired detective with the Bristol Criminal Investigation Division. The son of a former detective, he approaches police work with rigid detachment, refusing to let cases penetrate his emotional armor. The intense pressure of the missing child investigation triggers chronic insomnia and panic attacks, forcing him to attend mandatory psychological counseling.

Nicky is Rachel's energetic, forceful older sister. She runs a successful food blog while managing her husband and four daughters. Viewing Rachel as fragile, Nicky immediately moves into Rachel's home to act as a buffer against the press and the police, taking charge of the domestic chaos.

Emma is a Detective Constable with an attractive, calm demeanor that naturally puts anxious people at ease. She acts as the bridge between the police force and the Finch family, spending extensive time at Rachel's house. Privately, she maintains a secret romantic relationship with the lead investigator, Jim Clemo.

John is a pediatrician and Rachel's ex-husband, having left her ten months prior for another woman. He presents a polished, sometimes arrogant front to the world and firmly believes in rigid, structured parenting. He is quick to condemn Rachel's decisions and views her emotional displays as detrimental to the search.

Joanna is an attractive, well-groomed woman in her early thirties who teaches at Ben's primary school. She presents an articulate, tactful persona and is highly regarded by the administration. She earned Ben's deep affection by helping him navigate the emotional turmoil following his parents' divorce.

Dr. Manelli is a police psychologist tasked with evaluating and treating Jim Clemo. Operating entirely through session transcripts and clinical notes, she functions as an objective observer of the investigation's toll on the detectives. She patiently attempts to dismantle Jim's defensive barriers.

Katrina is a nutritionist who married John Finch after he left Rachel. Always impeccably dressed and poised, she is the physical opposite of the exhausted Rachel. She goes to great lengths to ensure Ben feels comfortable during his visits, challenging Rachel's assumptions about her character.

Laura is Rachel's best friend and works as a gossip columnist. Given her background in media, she attempts to advise Rachel on how to project a sympathetic image to the press. Her career in journalism eventually causes tension as Rachel's paranoia regarding media leaks grows.

Corinne Fraser is a Detective Chief Inspector overseeing the entire Finch investigation. She acts as the primary strategist for the police department, juggling public relations, media damage control, and internal team dynamics. She demands rapid results and strictly manages her detectives' interactions with suspects.

Woodley is a junior detective working under Jim Clemo and Corinne Fraser. He performs essential legwork for the investigation, conducting interviews and eventually taking over family liaison duties when required.

Bennett is a detective on the Bristol force who assists with witness transport and interviews. He maintains an even temper, functioning as a stabilizing presence when dealing with agitated civilians.

Damien Allen is the headmaster at Ben's school. A classic bureaucrat, he offers the police standard administrative assistance but provides very little insight into the personal lives of his students or staff.

Lucas is a teaching assistant at Ben's primary school, working closely with Joanna May. He draws police suspicion when his alibi for the time of the abduction proves inconsistent.

Simon is Nicky's husband and the father of their four daughters. While Nicky immerses herself in Rachel's crisis, Simon is left to manage the domestic strain of their over-scheduled family life.

Ruth is John Finch's mother and Ben's grandmother. Suffering from dementia, she resides in a local nursing home. Rachel maintains regular visits with her, carefully shielding her from the traumatic news of Ben's disappearance.

Skittle is the Finch family dog. He accompanies Rachel and Ben on their autumn walk and is the only physical witness to the abduction, later found injured near the scene.

Edward is a member of a fantasy role-play group called the Knights of Isthcar. Because his group was active near the area where Ben vanished, he briefly becomes a suspect in the police investigation.