Content Warning: This section of the guide discusses mental health conditions, sexual abuse, and psychological abuse.

Billie is the novel's main protagonist, and much of the narrative is written from her first-person perspective. Her character epitomizes the pursuit of identity beyond societal expectations. The description of Billie’s typically unostentatious appearance—"Grungy white Vans, no makeup, a New Yorker tote bag hanging from her shoulder” (95) —establishes her disinterest in the judgment of others. Billie’s immunity to convention is further illustrated by her decision to remain childless at the age of 35. The other characters’ reaction to this choice illustrates how childless women of a certain age are stigmatized by society. Billie’s job as a consultant arranging “luxury vacations for the one percent” fulfills her love of travel but sits uncomfortably with her social values (140). Her idea to introduce a charitable component to the business demonstrates her desire to contribute positively to society.

Billie is shaped by the traumatic events of her childhood. The importance she places on Cassie’s friendship is inextricably linked to her mother’s early-onset Alzheimer's and the sexual abuse inflicted by her stepfather. Having lost her family, Billie perceives Cassie as the one consistent feature of her life.