Toby is a hepatologist at St. Thaddeus hospital who recently separated from his wife of 15 years. He attempts to fulfill demanding professional responsibilities, including treating a rare Wilson's disease case, while meeting his children's needs in the wake of their mother's sudden disappearance. Having felt physically insecure in his youth, he heavily uses dating apps, swiping on women whose online personas often differ from their real-world selves.

Rachel is a highly successful talent agent who built her own company after facing workplace sexism early in her career. Raised by an emotionally cold grandmother, she places immense value on financial security, networking, and social mobility. Her sudden retreat to Kripalu sets off a logistical crisis for Toby, who views her ambition as a personal failing.

Hannah is Toby and Rachel's 11-year-old daughter. She reacts to her parents' divorce with outward hostility, frequently clashing with her father over minor inconveniences like walking instead of taking a cab. She depends heavily on her mother and struggles to manage her anger as Rachel's absence lengthens.

Solly is the nine-year-old son of Toby and Rachel. Unlike his sister, he processes the sudden changes in his family dynamic internally. He maintains a sweet disposition, showing curiosity about the world and offering quiet reassurance to his father while avoiding outright rebellion.

Libby is a former men's magazine journalist who lives in the New Jersey suburbs with her husband and children. She acts as both an observer of Toby's life and an active participant in his social circle. She formerly worked at a men's magazine, an experience that informs her critical perspective on gender dynamics in relationships.

Seth is a bachelor who became close friends with Toby and Libby during college. He works in finance but faces recent professional instability. He enjoys an active dating life and represents the kind of unattached freedom Toby is just beginning to experience.

Sam is a wealthy, well-connected businessman. He moves comfortably among the upper echelons of society, wielding influence through his money and social standing. He views ambition as an attractive quality and routinely mixes his professional power with his personal interests.

Nahid is an Iranian woman who immigrated to the United States as a child. She connects with Toby on a dating app, sending him sexually suggestive messages. She keeps her personal life strictly contained within her apartment, refusing to be seen in public due to an ongoing separation from her husband.

Cyndi is a wealthy mother embedded in Manhattan's elite social circles. She represents the superficial, status-obsessed lifestyle that Toby dislikes but Rachel aspires to join. She occasionally offers Toby unwanted attention or social invitations following his separation.

Miriam is Sam's wife and a highly influential figure in Rachel's desired social sphere. Her immense wealth dictates her lifestyle, though her husband privately complains about her lack of professional drive.

Joanie is a young, dedicated medical fellow training under Toby at St. Thaddeus hospital. She demonstrates sharp clinical instincts and genuine enthusiasm for complex medical cases like Wilson's disease.

Karen is a 44-year-old woman admitted to the hospital following a weekend trip to Las Vegas. She suffers from Wilson's disease, a rare liver condition that requires intensive medical intervention. Her unconscious state leaves others to speak for her.

David is a tall, important man who brings his wife to the hospital when she exhibits bizarre symptoms. He demands clear answers from the medical staff and struggles to understand the severity of his wife's condition.

Donald is the tall, muscular chief of hepatology at St. Thaddeus. He holds significant authority over Toby's career advancement and prioritizes the satisfaction of important patients' families.

Simone is Rachel's professional assistant. She acts as a strict gatekeeper, shielding her boss from unwanted inquiries and managing her logistical needs.

Mona is the Fleishman family's longtime nanny. She provides essential childcare but eventually runs afoul of Toby's strict disciplinary expectations when an incident occurs under her watch.

Vanessa is Seth's young, warm, and highly attractive girlfriend. She integrates smoothly into Seth's friend group and provides a stabilizing presence in his otherwise chaotic bachelor life.

Tess is a woman with dyed blond hair whom Toby meets at a bar called Dorrian's. She recently separated from her husband due to differing sexual interests and engages in a brief, casual encounter with Toby.

Todd is Cyndi's husband, embedded in the same wealthy social strata as Sam Rothberg. He attempts to maintain cordial ties with Toby despite Toby's disdain for their social circle.

Lexi is the daughter of Cyndi and Todd Leffer. She provides Hannah with an escape from Toby's apartment through sleepovers.

Barbara is Toby's lawyer. She occasionally forgets the specifics of his case and offers contradictory advice, highlighting the chaotic and uncontrollable nature of his legal situation.

Amy is Karen's best friend. She accompanied Karen on a trip to Las Vegas and provides Toby with crucial personal context about Karen's unhappy marriage.

Alejandra is a famous stage actress whose career Rachel launched. Her success firmly established Rachel's reputation and financial independence in the talent agency world.

Matt is Rachel's former employer and current industry rival. He represents the systemic sexism Rachel faces, having penalized her for pregnancy before later poaching her star client.