Bye, Baby (2024) is a domestic thriller by American author Carola Lovering. The story centers on the dramatic unraveling of the once-close friendship between Billie West and Cassie Barnwell, set against a backdrop of jealousy, betrayal, and high society in New York City. The tension reaches a peak when Cassie's baby disappears, revealing the dark undercurrents of a toxic relationship. Against this background, Lovering explores Class and Social Mobility, The Shifting Dynamics of Friendship, and The Consequences of Concealing the Truth.

This guide refers to the 2024 St. Martin’s Press eBook edition.

Content Warning: The source material includes depictions of toxic relationships, mental health conditions, sexual abuse, and psychological abuse.

Plot Summary

In the story’s Prologue, Billie sits in an apartment with Ella, her friend Cassie’s baby. Cassie screams from the apartment above and calls Billie’s cell phone.

The novel features two timelines: the weeks preceding Billie’s abduction of Ella and the backstory of Billie and Cassie’s childhood friendship. The narrative viewpoint alternates between the protagonists, Billie and Cassie.

In the more recent timeline, Billie feels increasingly shunned by Cassie, who rarely responds to her messages. Cassie is an Instagram influencer with her own boutique clothing store, and Billie is addicted to following her content. She is delighted when Cassie invites her to a dinner party. However, Billie and her boyfriend, Alex, feel out of place among the wealthy guests. Cassie’s husband, Grant, is a hedge fund manager from old money, and Cassie’s new best friend is Grant’s cousin, McKay. Afterward, Cassie posts a photograph of the dinner party in which Billie and Alex have been edited out.

During a rare visit to see her parents in Red Hook, Cassie posts a picture of the river. She is disturbed to receive a response from an account she does not recognize, suggesting that she is returning to the scene of a former crime.

Cassie does not invite Billie to her 35th birthday party. On the night of the party, Grant puts Ella in her stroller on the apartment terrace. Meanwhile, Billie’s boss and close friend, Jane, has gone to Iceland with her wife, Sasha. Jane and Sasha have recently moved to the apartment below Cassie’s. Billie is due to meet Alex for dinner but has promised to feed Jane’s cat first. She checks Instagram and is devastated to see Cassie’s live footage of her birthday party. Billie feeds Jane’s cat and hears a baby crying over the noise of Cassie’s party. She climbs up the fire escape, takes Ella from the terrace, and returns to Jane’s apartment.

In the earlier timeline, Billie and Cassie become best friends when they meet in their hometown of Red Hook as 12-year-olds. They frequently watch the movie Dirty Dancing and call one another “Baby” after the main character. Cassie has had ambitious social aspirations from a young age. Her father was born into a wealthy family, but when he lost his money, Cassie’s grandmother, Catherine, cut him off, and the family moved from Greenwich to Red Hook. Cassie idolizes Grandma Catherine and blames her father for their loss of social status. When Grandma Catherine disapproves of her boyfriend, Kyle, Cassie breaks up with him.

Billie’s mother, Lorraine, is diagnosed with early-onset Alzheimer’s and marries her boyfriend, Wade. As Lorraine’s cognitive function swiftly deteriorates, Wade sexually assaults Billie. While Cassie is offered a place at Harvard due to her family connections, Billie accepts a place at Northeastern. However, Wade states he must use Billie’s college fund to pay for a live-in nurse. Billie agrees to stay at home, study at SUNY New Peltz, and tolerate Wade’s sexual abuse if he keeps her mother at home. One day, Wade catches Billie and Cassie smoking on the widow’s walk on the roof. When Cassie calls Wade a rapist, he responds by asserting that she will never escape Red Hook. Cassie shoves Wade toward the walk’s rotten railings, and he falls to his death. Billie and Cassie lie to the police, claiming they were studying in Billie’s bedroom when Wade fell.

In the present timeline, Billie escapes Jane’s flat and leaves Ella outside Cassie’s door, wearing her boss’s hat to conceal her identity. Despite Ella’s swift return, Cassie is consumed by anxiety and believes the abduction is related to Wade’s death. She refuses to leave the apartment and ignores all messages except Billie’s, who drops everything to stay with Cassie. Detective Barringer, the officer overseeing the kidnapping case, thinks a group of teenagers abducted Ella. Cassie is unconvinced, and Alex, who is a police officer, offers to investigate.

In the earlier timeline, Billie is studying at Northeastern but often spends weekends at Harvard. Cassie is trying to befriend the well-connected McKay. Billie falls in love with an artist and life-drawing model, Remy. She does not tell him that she was sexually abused, but the relationship helps her to come to terms with her trauma. Cassie dates a fellow student named Jay but ends the relationship when she discovers his family is not as wealthy as she believed.

Back in the present, Cassie fires her housekeeper and nanny, Lourdes, as she no longer trusts anyone around Ella apart from Billie. McKay is suspicious of Billie and suggests she may have been involved in the kidnapping, but Cassie refuses to consider the possibility. After arguing with Grant, Cassie books a weekend trip for herself, Billie, and Ella, and Billie cancels her plans with Alex to go. At the hotel, Cassie confesses her fears about the mysterious Instagram comment. However, Billie recognizes the account name as an old school friend, and Cassie realizes the message was not intended to be sinister. Cassie apologizes for distancing herself from Billie, admitting she wanted to leave behind everything connected to her past life in Red Hook. Cassie reverts to calling Billie “Baby” and invites Billie and Alex to Grant’s family villa in St. Barts the following weekend.

In the earlier timeline, Billie and Remy move in together. When Remy says he wants children, Billie confesses that she never wants to be a mother, and they break up. Soon afterward, Billie’s mother dies. Meanwhile, McKay introduces Cassie to Grant. When Grant tries to seduce Jane, Billie tells Cassie, who refuses to believe her. The friends eventually reconcile, but the relationship never fully recovers, and Cassie asks McKay to be the maid of honor at her wedding.

In the present, McKay visits Cassie after speaking to Detective Barringer. She reveals that Billie was supposed to feed her boss’s cat on the night of the party and that Jane lives directly below Cassie. Billie and Alex go to a concert, and Billie wears Jane’s hat, which she used to disguise herself after the abduction. After the concert, they bump into Jane and Sasha. When Sasha asks when Billie borrowed the hat, Alex realizes that Billie lied about her movements on the night of Cassie’s party. Billie admits everything to Alex, who says he never wants to see her again.

Billie turns up at the airport, ready to leave for St. Barts. Cassie confronts her, and Billie confesses to abducting Ella. Cassie boards the plane alone, declaring their friendship is over. Billie watches the plane take off without her.

Cassie resumes her former lifestyle, posting on Instagram and feeling grateful for her marriage to Grant. She is relieved at the prospect of never seeing Billie again, as she can put the circumstances of Wade’s death behind her. Cassie decides not to press charges against Billie as they are now “even.” Billie visits Alex in New York, who reveals that he still loves her. She admits that she does not want kids, but Alex is undeterred, saying that he does not have his heart set on parenthood.