You'll Be the Death of Me

You’ll Be the Death of Me is the sixth book by best-selling young adult novelist Karen M. McManus. The novel tells the story of three former friends—Mateo Wojcik, Ivy Sterling-Shepard, and Cal O’Shea-Wallace—whose impulsive decision to skip school has deadly consequences. As the trio try to solve the mystery and clear their names, they each struggle to hide secrets of their own. Major themes in the novel include the Ethical Problems With True Crime, the Rewards and Risks of Trusting Instincts, and Tensions Inherent in Parent-Teen Relationships. The narration alternates between the perspectives of the three protagonists with the subtitle of each chapter indicating the narrative point of view.

This summary is based on the 2021 Random House e-book edition.

Content Warning: The novel contains depictions of violence, drug use, and inappropriate teacher-student relationships.

Plot Summary

One day after losing her senior class election at Carlton High, perfectionist Ivy prepares to speak at her mother’s award ceremony. Her former friend Mateo works two jobs to support his disabled mother, whose failing business was bought by Ivy’s developer father. When Cal, a lonely artist mourning a breakup, runs into Ivy and Mateo by chance, he convinces them to skip school and drive into Boston. There, the trio spots the newly elected class president, Brian “Boney” Mahoney, who is also skipping school. At Ivy’s insistence, they follow Boney into a locked building. Curiously, Cal’s new fling has a studio in the same building. When they find what appears to be Boney’s body in an abandoned room, Ivy faints, and Cal and Mateo carry her to a nearby dive bar, where Mateo works. There, they learn that police swarmed the building following an anonymous tip about a blonde woman injecting a teen boy with an unknown substance. Ivy wakes up furious that Cal and Mateo fled the scene. She asks Cal if his mysterious older girlfriend is blonde. Cal won’t answer but reveals that he found a phone at the scene.

When Cal says he needs to leave, Mateo and Ivy decide to follow. At a Cambridge café, Cal meets and kisses Lara Jamison, his young, attractive, and blonde art teacher. Lara denies involvement in Boney’s murder, but she tells Cal to keep her studio a secret until she speaks to her friend Dominick, another artist in the building. When Mateo and Ivy confront Cal about his relationship with Lara, he spitefully brings up Mateo and Ivy’s first kiss and threatens to leave. Mateo reveals that, after their first kiss, he left her a note with her favorite candy to ask her out. Ivy believes her brother must have stolen it. As the trio walk through Boston, a reporter who knows Ivy’s family spots them.

Ivy reveals that she stole Lara’s planner. Inside, they find a list of Carlton High students: The names Brian Mahoney, Charlie St. Clair, and Mateo Wojcik are circled in red. Boney’s phone rings, and Cal answers, pretending to be him. The caller, Charlie St. Clair, is shocked to hear that Boney is alive, and asks whether the guy they were expecting showed up. When Cal admits he is not Boney, Charlie hangs up, and the trio decides to drive to his house. Mateo enters Charlie’s house alone and finds it ransacked. He follows a noise into the basement, where he finds Charlie. Charlie admits to selling opioids alongside Boney and Mateo’s cousin, Autumn. Mateo explains that Autumn began selling drugs to pay for his mother’s medicines but insists that he did not know Boney was involved. As tabloid reporting and social media rumors fly about the student council election and speculation about Ivy’s involvement in the murder becomes breaking news, Charlie reveals that Boney had planned to meet a big buyer at the studio.

Anxious that he hasn’t heard from Autumn all day, Mateo insists they try to find her. Mateo and Ivy learn that Lara’s friend Dominick Payne had a failing gallery saved from bankruptcy by a mysterious influx of cash. When the trio finds Autumn, Mateo tells her to go to New York, where his mother is visiting her sister, and convince their mother to stay away from Boston for a few more days. Overwhelmed by Mateo and Autumn’s sacrifices, Ivy guiltily admits that she caused the accident that led Mateo’s mother’s bowling alley to close. Furious, Mateo storms off as soon as the trio arrives at Carlton High. Ivy and Cal break into Lara’s classroom to try to learn more about Dominick Payne. They are interrupted by Ivy’s brother Daniel, who reveals that he lied to the police to protect Ivy. Prompted by Daniel, Cal admits that he stole the note and candy Mateo left for Ivy. Meanwhile, Mateo returns to find his own home ransacked. He also learns that Autumn plans to turn herself into the police instead of going to New York as he asked. He unlocks Boney’s phone using the code B-R-I-A-N.

At Carlton High, Cal suggests that Daniel was acting in his own self-interest by lying to the police, infuriating Ivy and causing her to storm off. Cal finds bags filled with pill bottles in Lara Jamison’s desk. Ivy leaves to pick up Daniel; when she arrives at what she believes is Daniel’s location, Lara’s fiancé and lacrosse coach, Tom Kendall, kidnaps her. At Stefan St. Clair’s house, Mateo confronts Autumn’s boyfriend Gabe, whom he discovers is the last person to have contacted Boney. After some threatening, Gabe finally admits that Tom Kendall is responsible for killing Boney. Meanwhile, Cal drives to Lara’s house to confront her about her involvement. She insists that she is being set up by Tom. When Tom arrives with Ivy, Lara convinces him to frame Cal and Ivy instead, and then kill them. Cal and Ivy fight back and are eventually rescued by police, who surround the home.

After Ivy admits that she caused the accident at the bowling alley, her father settles with Mateo’s mother, restoring their financial losses. Mateo’s mother reveals that she wanted the alley to close, as she felt overwhelmed by the responsibility of running it alone. Mateo and Ivy reconcile and begin dating. Cal and Ishaan Mittal, a high school YouTuber making videos about the case, begin a friendship. Mateo’s father returns and introduces Mateo to his new fiancée, whom he reveals to be Lara. Ivy vows to destroy her.