Who Killed Simon Kelleher in One of Us is Lying?

One of Us is Lying is a riveting teen mystery based on Karen M. McManus’ 2017 novel of the same name. This new series joins a list of many teen shows with exciting premises to hit streaming services. The series follows a Breakfast Club-esque group of five teens who walk into detention, but only four of them make it out alive.

Simon Kelleher (Mark McKenna) meets a quick and untimely demise during the first episode, which begs the question of how someone dies in detention. While death from boredom can be easily ruled out, in the show, Simon’s death is still much more complicated. In fact, the show has an even darker adaptation of Simon’s death than the book. A breakdown of how Simon died, who was responsible, if this follows the book ending, and whether Simon’s story continues in the second season follows.

What Happened to Simon Kelleher That Led to His Death

Simon Kelleher enters detention with braniac Bronwyn (Marianly Tejada), popular princess Addy (Annalisa Cochrane), jock Cooper (Chibuikem Uche) and misunderstood delinquent Nate (Cooper van Grootel). He appears completely healthy when he arrives in detention, and everything is pretty normal until he pours himself a glass of water from a water cooler. Soon after, the teacher running detention, Ms. Avery, runs out of the library to reprimand some students who are streaking and throwing eggs at a classroom window. While Ms. Avery is gone, Simon takes a sip of the water and goes into anaphylactic shock; there were traces of peanut oil in the water and Simon is deathly allergic. The four other students rush to get him an EpiPen, only to not find any in his backpack or in the nurse’s office. The four students have no choice but to watch helplessly as Simon struggles to breathe. An ambulance is called and Simon later dies in the hospital.

Possible Suspects Responsible For Killing Simon

Bronwyn, Addy, Cooper and Nate become the prime suspects in Simon’s murder. The other students at their school even nickname them with the ominous names of “The Bayview Four” and “Murder Club.” Nate is even wrongfully arrested when a bag of EpiPens are found in the seat of his motorcycle. But The Bayview Four have nothing to do with Simon’s murder. If The Bayview Four are innocent, then Simon’s killer remains a mystery. The real answer, however, has two parts to it.

Simon was the one who laced his own water with peanut oil. It was all meant to be a harmless but ruthless prank orchestrated by Simon to scare his classmates. He was intending to revive himself using one of the many EpiPens that he personally brought into the nurse’s office. But how exactly did a sick prank turn deadly for Simon? He had an accomplice to the prank. His old childhood friend, Jake (Barrett Carnahan), helped him concoct the plan through their Xbox gaming chats, and he was supposed to be waiting just outside the library with an EpiPen in hand to swoop in and save Simon’s life. Jake, however, was paranoid that Simon was recording their conversations. In order not to be linked to the prank, he removed all the EpiPen’s from the nurse’s office instead. Jake then takes the opportunity to frame his girlfriend Addy for murder as revenge for her cheating on him with his best friend TJ. Addy is far from a damsel in distress, however.

Addy uncovers Jake’s secret plot when she sees Simon’s old handle in Jake’s Xbox chat history. The Bayview Four try to steal the Xbox as evidence at a party that Jake throws, but Jake catches them and he holds Addy at gunpoint in the woods behind his house. Cooper and Simon’s best friend, Janae (Jessica McLeod), follow them to save Addy. A fight ensues, and the gun accidentally goes off. Jake dies from a gunshot wound, and they have to dispose of his body. Afterward, they all agree to go their separate ways and to not tell anyone what happened in the woods.

Simon’s Story Has a Different Ending in McManus’ Book

In the show, Jake is the evil mastermind behind Simon’s death. In the book, things aren’t quite as twisted. Janae reveals that Simon was majorly depressed, and he was obsessed with death. In the book, Simon intended to commit suicide under the guise of the ill-conceived prank. Simon wanted to use Jake to frame The Bayview Four for his murder, so Jake’s involvement wasn’t quite as sinister as the show’s version of events. Interestingly, Jake still pays for his involvement in Simon’s death when he gets arrested. The Bayview Four get a more positive ending, becoming free to live their lives without any more secrets. This is a direction the show didn’t take to prep a compelling cliffhanger for the second season.

How Simon’s Story Continues In Later Seasons

In the closing moments of the first season, The Bayview Four and Janae receive ominous text messages under Simon’s old gossip blog alias, “Simon Says,” announcing that they know what happened in the woods the night Jake died. The second season picks up with them trying to uncover identity of their new tormentor. Meanwhile, the student body at Bayview High speculate about Jake’s disappearance and his involvement in Simon’s death. One important thread to Simon’s story is left open-ended for a potential third season. Jake’s real motive for killing Simon might have been worse than wanting to frame Addy for murder. Simon could have stumbled upon Jake’s darkest secret: the reason Jake secretly spent the previous summer in rehab. Just like the second season, a potential third season would continue to explore Jake’s past. This could potentially even bring Simon back to wrap up the storyline of Jake’s true motive for killing him.

One of Us is Lying Season 1 and 2 are available to stream now on Peacock.