Katie is a 25-year-old ghostwriter living in New York City, working for the famous romance author Meredith Bradford. She presents a bright, colorful exterior to the world by focusing on her career and casual dating to avoid processing her family history. Her carefully organized life is disrupted when she is forced to collaborate with a boy from her past she has not seen in eight years.

Tyler is an Ivy League-educated literary fiction author who accepts a ghostwriting job to make ends meet after his own manuscript fails to sell. He is nine years sober and carries deep guilt over the circumstances surrounding his former best friend's death. Though initially cynical about the romance genre, he agrees to the project out of financial necessity and a lingering connection to his past.

Meredith is the world's most famous and reclusive romance novelist. She lives in a sprawling, isolated estate in Southampton with her cat, Pinot, and avoids public life entirely. Eccentric and commanding, she controls the parameters of Katie and Tyler's writing project by using unconventional methods to assign their plot points.

Carolyn is Katie's mother, a woman entirely consumed by grief following the death of her son eight years earlier. She channels her energy into running a memorial foundation and planning its annual fundraising gala. Her intense focus on preserving her son's memory leaves her unable to offer emotional support to her living daughter.

Danny is a successful lawyer who dates Katie casually. He enjoys a superficial relationship with her and remains largely unaware of her family history or the trauma she carries. He easily becomes jealous of the time she spends working with her new writing partner.

Arthur is a gruff older man who serves as Tyler's sponsor in Alcoholics Anonymous. He provides practical grounding and direct advice, holding Tyler accountable for his actions. He encourages Tyler to face personal history honestly rather than running away from difficult situations.

Mikey was a promising high school baseball pitcher before a severe injury ended his career. His subsequent struggles with addiction and eventual death cast a long shadow over the surviving characters. His memory dictates the dynamics of his family and friends long after his passing.

Selma is a high-profile literary agent who manages both Meredith Bradford and her ghostwriters. She is strictly professional and fiercely protective of her clients' deadlines. She uses her industry leverage to force Katie and Tyler to collaborate despite their personal history.

Lola is Katie's roommate and a barista at Georgina's café. She is observant and protective of Katie. She often offers blunt advice about Katie's dating life and her tendency to avoid emotional vulnerability.

Paul is Katie's father. Following the loss of his son, he has retreated inward, becoming emotionally distant and disengaged from his family's daily life. He quietly exists in the background of his wife's frantic mourning.

Ingrid is Mikey's former high school girlfriend, now attending medical school and celebrating her upcoming wedding. She represents a healthy path forward from grief, having successfully moved on with her life while still honoring her past.

Pinot is Meredith Bradford's pet cat. He plays a bizarre but specific role in his owner's creative process, physically pulling slips of paper from a bowl to randomly select the romance tropes that dictate her ghostwriters' new project.

Pedro is a close friend of Tyler's from his recovery group. He provides a supportive sounding board and occasionally challenges Tyler to examine his personal shortcomings when it comes to dating and writing.

Tom is Tyler's estranged father. His early departure from the family left a deep impact on Tyler's self-worth and fears about relationships.

Marcy is Tyler's mother. She appears in flashbacks attempting to navigate the difficult circumstances of her son's recovery and the surrounding community fallout.