Emma is a highly educated intertidal ecologist who recently completed treatment for low-grade cancer. Having lost her parents at a young age, she struggles with a sense of rootlessness but loves her husband and daughter with fierce, protective intensity. She is a highly private individual who keeps certain aspects of her life locked away in a personal folder. Her work studying habitats submerged at high tide reflects her own comfort with solitude and uncertainty.

Leo is a kind, patient man who works as an obituary writer for a local paper. He uses his profession as a coping mechanism, pre-writing obituaries to manage his anxiety about his wife's health. He discovered his own adoption by accident early in adulthood, an event that deeply strained his relationship with his parents and left him feeling like an outsider in his own family.

Jeremy is a public figure and radio personality who finds himself at the center of public speculation when his wife goes missing. He is intensely devoted to his marriage and will go to great lengths to protect his household. He occasionally acts with brutal honesty and defensiveness when interacting with the media.

Janice is a famous actress who has disappeared without a trace, sparking a local media frenzy. She struggled with fertility issues before welcoming her son and is intensely dedicated to motherhood. Her disappearance sets off a chain of inquiries that uncover long-buried anxieties she documented in her personal diaries.

Charlie is a university student studying in Boston who returns home and becomes deeply concerned about his mother's sudden disappearance. He is observant and begins seeking answers when he notices strange behaviors and discovers old diaries at his family home.

Ruby is the three-year-old daughter of Leo and Emma. She is a cheerful, imaginative child who brings joy and grounding to her parents' lives while they navigate health struggles and career demands.

Jill is a university friend of Emma who has known her for decades. She is highly organized and fiercely loyal, often helping Emma handle difficult situations and serving as a sounding board, even if it requires keeping secrets.

Sheila is Leo's perceptive coworker who is rumored to be a former spy. She has a strong network of connections, including a friendship with the Rothschild family, and often provides Leo with crucial information and a place to rest when he is overwhelmed.

Gloria is Emma's late maternal grandmother and a groundbreaking female Member of Parliament in the 1950s. She was a minor hoarder whose accumulated belongings still fill Emma's home, and she provided crucial stability for Emma after her parents' deaths.

John Keats is the family's anxious rescue dog. He requires a calm environment and music to soothe his nerves, serving as a gentle presence in the household.

Kelvin is Leo's editor at the local paper. He is pragmatic about news coverage but harbors a slight crush on Emma, largely due to her past television work.

Mags is a talent agent who previously represented Emma during her time as a BBC television host. She is a busy professional who is hesitant to discuss past client relationships with journalists.

Robbie is a former series runner for the BBC show Emma once hosted. He currently lives in Glasgow and attends death conferences, holding his own theories about Emma's sudden departure from television.

Olly is Leo's brother, who leads a chaotic family life with unruly and undisciplined children. He provides a stark contrast to Leo's quiet, tightly-knit household.

Leo and Olly's mother relies on her family for support when her husband falls ill with the flu. Her relationship with Leo has been permanently strained since he discovered family secrets.

Leo and Olly's father is an aging man whose illness requires Leo to temporarily leave home to assist with his care.

A military chaplain who fell into a deep depression and alcoholism after the death of his wife. His transient military career and struggles with addiction created an unstable childhood for his daughter.

David is Jeremy's cousin. He is an older, married man who had a brief connection with Emma during her university years but refused to take responsibility for the fallout.