The following version of this book was used to create this study guide: McManus, Karen. You’ll be the Death of Me. New York: Random House, 2021.

The novel is composed of 36 chapters that alternate between three narrators who tell the story in first-person present. Ivy, Cal, and Mateo became best friends in sixth grade when they skipped a school field trip to have "The Greatest Day Ever." By senior year, the three are no longer friends, and each of them are fed up with Carlton High School. Ivy is upset that she lost the election to joker Boney Mahoney. Mateo is exhausted from working several jobs and stressing about his cousin, Autumn, who is selling drugs to pay for his mother’s medical bills. And Cal is dating an older woman who he is obsessed with, but who seems to be bad for him. When the trio runs into one another in the parking lot before school, they impulsively decide to skip school together and go to Boston.

They wander around, seemingly aimlessly, and eventually Cal leads them toward the art studio in a big building where his older girlfriend works on Tuesday mornings. Ivy sees Boney Mahoney go inside. Angry, she follows him inside to yell at him about the election. Cal and Mateo follow her, but by the time they get upstairs to the studio they discover Ivy standing over Boney Mahoney, who is dead. Ivy faints and the police arrive downstairs. Cal and Mateo carry Ivy out the back and rush to Garret’s, the bar Mateo works at. They turn on the news and learn that the police got a call about an anonymous woman injecting a young man with a syringe. When they arrived, they found Boney Mahoney dead. Ivy wakes up and the trio tries to figure out who the blonde woman in the news was. Cal admits that his older girlfriend is indeed blonde, but he refuses to believe she had anything to do with Boney’s death. He texts her and then leaves to go see her in Cambridge. Ivy and Mateo follow Cal and discover that his mysterious older girlfriend is none other than Ms. Lara Jamison, their high school art teacher who is engaged to the high school lacrosse coach.

Ms. Jamison tells Cal that she was at a ceramics class when Boney had been killed. Ivy and Mateo distract her and steal her day planner. When Cal leaves, Mateo and Ivy follow him and confront him on the train back to Boston. She scolds him for being involved with a teacher and he tells her she knows nothing about love since the last person she ever kissed was probably Mateo way back in eighth grade. With the past dredged up, Ivy and Mateo talk about the kiss that destroyed their friendship. Mateo admits he left Ivy a box of her favorite candies and a note asking her to the movies right after the kiss, but she had never responded to him. Ivy reveals that she never received the note or the candies, so she imagines that her brother must have stolen the candy and thrown the note away.

The trio goes to Crave Donuts and looks through Ms. Jamison’s day planner. They find a love note signed “D” and class roster with the names of Boney, Mateo, and Charlie St. Clair. They decide to track down Charlie St. Clair and end up at his house, which has been completely raided. They take him to Ivy’s house, and he reveals that he found a stash of 100 bottles of Oxycontin at a a party at an abandoned house the month before. He, Boney, and Autumn had been selling the pills together. The night before, Boney had received a call from a buyer who wanted to meet him in Boston for a huge purchase. Autumn had warned Boney not to go, but he had gone anyway and now he was dead. Charlie adds that he believes there is a big drug lord working in the area who employs a “Weasel” at the high school so they can stop any small operations from popping up.

The trio believes Ms. Jamison is involved with the drugs somehow but cannot quite believe she is the drug lord. They wonder if the anonymous “D” might be the culprit. After meeting up with Autumn to warn her about the danger, the trio heads back to school to search through Ms. Jamison’s room. However, on the way, Ivy, who has felt guilty all day, reveals that she is to blame for an accident that led to Mateo’s mom’s bowling alley being sued the previous year. Mateo is so angry that he tells Ivy he never wants to talk to her again and storms away.

Ivy and Cal continue on with the search of Ms. Jamison’s room, but they do not find anything interesting. Ivy’s brother, Daniel, catches them in the room and demands to know what is happening. After he leaves to go to Olive Garden with his friends, Cal hypothesizes that Daniel might be “D.” Ivy gets frustrated with him and also leaves to go home.

Cal stays in the room and finds a collection of pills inside Ms. Jamison’s desk. He takes them to go to her house and confront her. Ivy gets a text from her brother asking her to help him because his friend’s car broke down. When she arrives at the spot, Coach Kendall grabs her. Ms. Jamison reveals to Cal that her fiancé, Coach Kendall, is the drug lord. Meanwhile, Mateo realizes that Autumn’s boyfriend is the Weasel. Mateo confronts him and also learns that Coach Kendall is the drug lord.

Coach Kendall gets a gun and takes Ivy, Cal, and Ms. Jamison into his garage where he reveals that he wanted to kill Boney to frame Ms. Jamison but his plan got ruined. At first, he plans to kill them all, but then Ms. Jamison suggests they kill the teenagers and escape guilt together. Coach Kendall agrees to this new plan, and nearly kills Cal, but then the police, who were called by Mateo, arrive and save the day.

Coach Kendall is arrested, but Ms. Jamison escapes arrest because she pins everything on her fiancé. Ivy and Mateo become a couple. His father, Darren, moves back into town permanently and takes the young couple out to lunch to meet his new girlfriend. Ivy and Mateo are horrified when they learn that Ms. Jamison is dating Mateo’s father.