Hannah is a 32-year-old interior designer living in Atlanta, Georgia. Raised by wealthy parents who heavily prioritize appearances, she frequently tries to please others and struggles to assert her own needs. She strongly desires a traditional family life and feels her world shatter when she discovers her fiancé is cheating on her. Within her close-knit friend group, she acts as the natural peacekeeper and cheerleader, often putting her friends' well-being before her own.

Lainey is an aspiring actor from California who uses boldness and humor to mask her deep emotional insecurities. Growing up with a single mother who loved a married man, she learned early that her father had a second family, a secret that left her terrified of rejection. She frequently uses alcohol and casual encounters as a shield against genuine connection. Despite her chaotic personal life, she drops a major career opportunity without hesitation to rush to Hannah's side during a crisis.

Tyson is a meticulous trial lawyer working in Washington, DC. As the son of high-powered attorneys, he holds himself to exceptionally strict personal and professional standards, keenly aware of the extra scrutiny he faces as a Black man in his field. He acts as the logical, rule-abiding anchor for his friends, though he quietly suppresses his own desires to meet external expectations. When Hannah faces a crisis, he risks his career and a serious romantic relationship to honor his commitment to his college friends.

Summer is an ambitious Midwestern athlete who ran track and cross-country during college. Described as the sun of the friend group, she was warm, highly driven, and strictly self-critical about her academic and athletic achievements. Her tragic death by suicide just before college graduation unites the remaining friends in shared grief, prompting them to form a solemn pact to always support one another.

Grady is a man who superficially meets all of the social expectations for a suitable husband in Atlanta. He destroys his engagement to Hannah when she catches him being unfaithful. Rather than taking full accountability, he makes excuses, complains about their relationship, and attempts to manipulate the situation to maintain his reputation.

Olivia is a professional tennis player currently training in Italy. She is Lainey's younger half-sister, though the two grew up entirely separate from one another. She maintains a healthy distance from her immediate family due to political differences and a need for independence. She is warm and approachable, quickly forming an authentic connection with Hannah.

Ashley is a mother of triplets living a comfortable, stable family life in Dallas, Texas. She is Lainey's half-sister and reacts with deep hostility when Lainey arrives unannounced to reveal the family secret. She is intensely protective of her conventional family unit and her parents' long marriage.

Mrs. Davis is Hannah's demanding mother, residing in Atlanta. She frequently prioritizes how situations appear to other people over her daughter's emotional well-being. She pushes Hannah to forgive Grady's infidelity purely to save face socially.

Berlin is Grady's neighbor in Atlanta. She becomes entangled in the central conflict when Hannah catches her in a compromising position. Lainey later orchestrates a dinner meeting to force Berlin to confess her knowledge of the existing engagement.

Nicole is a lawyer living in Washington, DC. She issues a strict ultimatum when Tyson decides to drop his work to support his college friend, resulting in the abrupt end of their romantic relationship.

Archie is a handsome Scottish tourist visiting the island of Capri. He provides Hannah with a welcome distraction and an opportunity to practice flirting after her difficult breakup in Atlanta.

Ian is an energetic tourist visiting Capri alongside Archie. He immediately takes an interest in Lainey during a night out, though Lainey views him primarily as a joke.

Alessandro is the capable local concierge at the friends' hotel. He helps arrange their dinners and provides vital translation and navigation assistance when a crisis occurs on the island.

Sharon is a married woman living in Texas who initially mistakes Lainey for an actor. She has spent thirty-five years married to Lainey's father, entirely unaware of the existence of his previous affair and his first daughter.

Gus is an attractive young man at a hotel bar in Texas. He serves as a convenient distraction for Lainey following a painful and highly emotional family confrontation.

Martin is a demanding law firm boss in Washington, DC. He represents the intense professional pressure in Tyson's life, showing zero leniency when Tyson needs time off for a personal emergency.

Marcus is Lainey's neighbor in California. He serves as a casual hookup for Lainey, representing her deep-seated tendency to avoid serious emotional attachments.