Laurel is a middle-aged woman struggling to find purpose ten years after the sudden disappearance of her teenage daughter. She works part-time, lives in a small flat, and spends her days managing a lingering grief that colors her worldview. Her profound sorrow and pessimism have severely strained her family ties, leaving her disconnected from her remaining children and her ex-husband.

Noelle is an unmarried woman in her early forties who works as a math tutor. She lives in an unremarkable house in Stroud Green and struggles with feelings of inadequacy stemming from a childhood spent in a deceased sister's shadow. She exudes an off-putting odor of cooking oil and tries desperately to forge a romantic connection with a local author.

Floyd is an author and mathematician known for his polite demeanor and tasteful clothing. Having experienced a nomadic and unmoored childhood with young parents, he struggles with deep-seated feelings of isolation. He homeschools his youngest daughter and makes a concerted effort to build a relationship with Laurel.

Ellie is a bright fifteen-year-old student whose sudden disappearance shattered her family ten years prior. Before vanishing on her way to the library, she was a popular teenager with a steady boyfriend and a promising future. She possesses an intuitive nature that makes her wary of certain adults in her orbit, though she often tries to see the best in people.

Poppy is a nine-year-old girl who bears an uncanny physical resemblance to Ellie Mack. Homeschooled by her father, she displays an unusual level of maturity, speaks with precocious self-assurance, and shares a dark philosophical outlook on life. She lacks a relationship with her mother, who reportedly vanished when she was a toddler.

Paul is Laurel's ex-husband, who eventually left the marriage when he could no longer cope with the stagnation caused by their shared grief over Ellie. He has since built a new life with a new partner but maintains a connection with his children. He dresses sharply and hopes for his ex-wife's eventual emotional recovery.

Hanna is Laurel's eldest daughter, a young woman who has grown accustomed to living in the shadow of her missing sister. She maintains a strained, distant relationship with her mother and often keeps her personal life entirely private. She carries quiet resentment over feeling like a consolation prize within her fractured family.

Jake is Laurel and Paul's son, who distanced himself from his mother's all-consuming grief following the family tragedy. He lives with his girlfriend and occasionally contacts his mother to check in or offer his perspectives on her new life choices.

Sara-Jade, frequently called SJ, is Floyd's older daughter from his first marriage. She has striking white-blonde hair and works as a nude model for drawing classes. She exhibits an aloof personality, frequently clashes with the adults in her life, and carries lingering animosity toward her father's past partners.

Theo is a bright young student who dates Ellie in the months before her disappearance. He excels at mathematics and features prominently in Ellie's thoughts as she anticipates their summer plans together.

Blue is Jake's girlfriend, possessing a highly perceptive nature that leads her to analyze the auras and energies of others. She freely offers her opinions on the people in Laurel's new circle, sometimes causing friction with her unsolicited observations.

Laurel's elderly mother lives in a care facility after surviving multiple strokes that have limited her vocabulary. She frequently expresses a readiness to pass away but finds brief moments of joy in seeing her daughter slowly rediscover happiness through a new relationship.

Bonny is Paul's partner following his divorce from Laurel. She acts as a welcoming presence in Paul's new life and accommodates his extended family, showing hospitality despite the awkwardness of the fractured family dynamics.

Joshua is Noelle's nephew who currently lives in his aunt's old house in Stroud Green with his brother. He assists Laurel with her questions about his missing aunt and allows her access to the property to look around.