Kate is a former intelligence field agent and analyst who retires when her family relocates to Luxembourg. She assumes the role of a traditional expatriate housewife but finds the isolation of domestic life stifling. Haunted by actions during her espionage career, she conceals her work history from her husband. Her observational skills remain sharp, causing her to quietly investigate the new people entering her social circle.

Dexter is Kate's husband and a security systems specialist. He accepts a position at a private bank in Luxembourg that promises a comfortable life for his family. He spends long hours working and traveling across Europe. He maintains strict discretion regarding his corporate clients, which sometimes creates distance in his marriage.

Julia is an American expatriate who moves to Luxembourg alongside her husband. She claims a background in interior design but states she cannot find work in her new country due to a lack of professional contacts. She quickly befriends Kate, sharing similar experiences of adjusting to life abroad.

Bill is Julia's husband who works in the financial sector in Luxembourg. He has an athletic presence and an appreciation for luxury goods. He spends a significant portion of his free time playing tennis with Dexter and socializing at local clubs.

Jake is the older son of Kate and Dexter. He relocates with his family to Luxembourg, where he attends a new school and adjusts to a different environment alongside his younger brother.

Ben is Kate and Dexter's younger son. He relies heavily on his mother as he settles into their new life in Luxembourg, often asking questions about their environment.

Hayden is Kate's former colleague from her intelligence career. He remains active in his profession and provides Kate with a crucial link to her past life. He maintains a network of contacts across Europe and serves as a sounding board for Kate's suspicions regarding the people in Luxembourg.

Adam is an interrogator for the Central Intelligence Agency. He questions Kate about her reasons for moving to Luxembourg and presses her for details regarding her past assignments in the field.

Evan is an intelligence interviewer who speaks with Kate during her exit process. He asks pointed questions about the deaths of her past targets, specifically regarding an incident in New York.

Joe is Kate's boss at the Central Intelligence Agency. He initiates the series of exit interviews she must complete before moving to Europe with her family.

Eduardo is a failed Mexican politician and presidential candidate. He went into exile in New York with hopes of eventually returning to overthrow his government. His interactions with Kate leave a lasting impact on her career trajectory.

Claire is an expatriate mother living in Luxembourg. She focuses entirely on her family and relies on the community of other mothers for support. She represents the typical domestic lifestyle that Kate tries to emulate.

Jane is an American woman living in Luxembourg. She interacts with Bill socially and attends functions at the American embassy, drawing Kate's attention during a quiet investigation.

Kyle is a contact of Hayden's based in Switzerland. He passes information to Kate while she is on a family skiing holiday, acting as an intermediary between her and her former agency.

Daniel is Dexter's older brother. He was an ex-Marine who worked as a mercenary and died in Croatia while Dexter was still attending college.

Lester is Julia's father who flies into Luxembourg for a visit. He asks Dexter about his job and expresses surprise at the limits of Dexter's banking salary during a group dinner.

Lorenzo is a man Kate trailed in Oaxaca, Mexico. He represents one of her earliest assignments and targets as a field agent, standing out in her memory as she reflects on her past.

Colin is Claire's son. He sustains an injury at a local playground, prompting his mother to take him to a clinic while leaving his sister in Kate's care.

Jules is Claire's daughter. Kate briefly looks after her when Claire takes Colin to a clinic, illustrating the communal reliance among the expatriate mothers.

Carolina is an expatriate mother living in Paris. She represents the typical lifestyle of the women in Kate's social circles, spending her time shopping and managing domestic affairs.