One of Us Is Lying Summary

One of Us Is Lying is a 2017 young adult novel by Karen M. McManus about a group of four high school students who are suspects in the mysterious death of a fellow student.

  • Five students at Bayview High School are sentenced to detention one afternoon. One student, Simon, dies from an allergic exposure. Cooper, Addy, Bronwyn, and Nate are suspects in his death.
  • It is revealed that Simon, who had run a gossip app, was preparing to post compromising information about the four students.
  • Cooper, Addy, Bronwyn, and Nate come together to solve the mystery and clear their names.


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Last Updated on January 27, 2021, by eNotes Editorial. Word Count: 1313

On a Monday afternoon, five Bayview High students find themselves assigned to after-school detention. Bronwyn Rojas is academically gifted, with Ivy League schools within her grasp after graduation. Cooper Clay, a kind-hearted boy originally from Mississippi, is a baseball superstar who is weighing his professional and collegiate opportunities. Addy Prentiss is at the top of the social ladder, a beautiful girl who has been dating her equally popular boyfriend, Jake, since their freshman year. Nate Macauley, already on probation for drug distribution, has a mother who is physically absent and an alcoholic father who is never coherent enough to help pay their bills. Simon Kelleher runs a gossip app which publishes consistently shocking and destructive—yet accurate—information about students in the school. Mr. Avery is in charge of the detention and ignores the students’ claims that they don’t deserve to be there; each student has been assigned detention for having a phone in Mr. Avery’s lab, which is strictly forbidden. Although they each show him their own phone in an effort to prove that the confiscated phones were planted on them, Mr. Avery insists that they have broken the rules and deserve to be punished.

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As they begin working on their assigned essays, Simon can’t find his water bottle and gets himself a drink from the back of the room. A car crash outside sends all the students to the window, and Mr. Avery goes outside to check on the drivers. Simon begins goading the other students with inflammatory comments before commenting that he is the “omniscient narrator” of the school, finishing his water in one long gulp. He quickly falls to the floor, wheezing and asking for his EpiPen. Desperately, the students begin searching for the pen, which is nowhere to be found. Mr. Avery returns, and a frantic search of the nurse’s office reveals that all of her EpiPens are missing. Simon is taken away by paramedics, and the group soon learns that he has died. An investigation reveals that the water Simon consumed in the room contained large amounts of peanut oil, which was a known allergy of Simon’s. Bronwyn, Cooper, Addy, and Nate find themselves persons of interest in a murder investigation.

Someone begins posting on Tumblr, claiming to be the murderer. This anonymous person claims that you can get away with killing someone whom everyone wants dead anyway. The students soon learn from the police that Simon had been ready to publish a new update on his app the day following his death, giving all four of them a motive for wanting Simon dead. Each of the four students was to be exposed in some way. Bronwyn cheated her way through chemistry by stealing tests off her teacher’s Google Drive. Nate violated his probation by continuing to deal drugs. Cooper reportedly improved his performance by using performance enhancers. Addy cheated on Jake with his friend, TJ. Everyone except Cooper acknowledges the truth in Simon’s unpublished words; Cooper wonders why Simon chose to lie for the first time on his app instead of revealing the actual secret that Cooper has been hiding.

The group of four students comes together to determine who actually murdered Simon; they feel that the authorities are overlooking clues because they are so intently focused on the four of them. Meanwhile, there are repercussions once Simon’s otherwise private post gains an audience. Addy tells Jake about her night with TJ, and Jake breaks up with her. Her friends side with Jake, and Addy plummets to the bottom of Bayview High’s social ladder. She begins attempting to connect with Janae, a social misfit at their school, after noticing how emotionally distraught she has been in the wake of Simon’s death; Simon was Janae’s only friend at Bayview. Nate and Bronwyn, who were once friends in elementary school, begin to reconnect, using burner phones so that Bronwyn’s socially elite parents won’t know that she’s talking to him. Cooper is called to the police station again, and the investigators suggest that he ask his father to wait outside. He agrees, fearing that they have discovered his actual secret. His fears are realized when they show him an encrypted file on Simon’s app that was prepared for publication but switched with the fake story about performance enhancers. Simon knew that Cooper is gay, and now Cooper will need to tell his father before the information becomes public to everyone. As he feared, Cooper’s secret seems to forever change his relationship with his father, who can no longer look him in the eye.

Nate is suddenly arrested when the nurse’s supply of EpiPens is discovered in his locker after the authorities receive an anonymous tip. Since his locker was searched and found to be empty after Simon’s death, Bronwyn is certain he has been framed. She, Cooper, and Addy begin meeting to go over any clues they have missed while Nate is held in a juvenile detention center; he refuses to have any contact with Bronwyn. As the group reads back through the Tumblr posts by the person posing as the murderer, Addy spots a lie that she had offhandedly mentioned to Jake. No one else would know about this, which implicates Jake in Simon’s death.

The group decides to track down the drivers involved in the car accident outside the school on that fateful day; Cooper discovers that it belongs to Sam, a student at another high school. Bronwyn goes to the school to talk to Sam, and he confesses that he was given a thousand dollars to fake the crash. Bronwyn shows Sam a photo of Jake, asking if he was the one who paid Sam the money. Sam sighs and reveals that Simon himself paid him.

The group meets again, this time bringing Kris, Cooper’s boyfriend, into their circle of confidence. They begin to consider Simon’s death some sort of suicide, with Jake acting as an accomplice of sorts. Addy decides to have an honest conversation with Janae, meeting her with sincere compassion. Janae seems relieved to finally confess the truth: Simon orchestrated his own death and intentionally framed the four of them. Janae tells Addy that Simon had always believed that he deserved more respect at school than he received, but after spending increasing amounts of time online in dark circles, he began to fantasize about revenge. Simon wanted to create a spectacular exit from the world that would make people remember him, and he generated an intentionally creative plan to accomplish his goals. Jake entered Simon’s circle of confidence after learning an embarrassing secret about Simon; Jake had used that information as leverage to include Addy in Simon’s plans for destruction. Simon left his manifesto with Janae with instructions to make everything public one year after his death and after he had destroyed the lives of the other students in the detention room with him that day. Jake suddenly shows up at Janae’s house and attempts to kill Addy, who is rescued by Cooper.

With the truth finally realized, Nate is released from the juvenile detention center but pushes Bronwyn away. Jake is incarcerated and charged with numerous crimes, and Janae works with the police, hoping for a plea bargain in exchange for her testimony. Bronwyn publicly acknowledges her cheating and sincerely apologizes for it, which catches the eye of Yale, who tweets that they look forward to her application. Addy fully recovers from the skull fracture she suffered at Jake’s hands and is content to be romantically unattached for a while. Cooper and Kris become a more visible couple, and Cooper’s father begins to show signs of acceptance. Nate eventually apologizes to Bronwyn for pushing her away, and they agree to begin by first repairing their friendship.

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