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One Of Us Is Lying Season 1 Ending Explained: Who Killed Simon?

Bronwyn, Addy, Cooper and Nate stand in front of their classmates at Homecoming in One of Us Is Lying
(Image credit: Peacock)

The new Peacock TV show, One of Us Is Lying, is a dramatic teen murder mystery with a fun premise: five students enter detention, and only four come out alive, after the school’s gossip king, Simon Kelleher, is murdered. This whodunnit — based on the book by Karen M. McManus — has everything you’d expect from either the best mystery movies or the best classic mystery shows: twists, turns, red herrings and plenty of motive. The One of Us Is Lying ending even leaves open the possibility for a Season 2.

So, who killed Simon Kelleher? The series centers around four suspects — the Bayview Four or Murder Club, as they’re not-so-affectionately called: Bronwyn (the smart one), Addy (the pretty one), Cooper (the jock) and Nate (the bad boy). Yeah, it’s a very Breakfast Club-stereotype situation, but the important thing to remember is that each of them had a reason to want to get rid of Simon. Let’s break down what happened at the end of Season 1 of Peacock’s One of Us Is Lying, and, obviously, there are MAJOR SPOILERS AHEAD, so consider yourself warned.

Simon talks into his Xbox headset on One of Us Is Lying

(Image credit: Peacock)

Who Killed Simon And Why?

It started out as a sick prank that Simon and his former friend, Jake, concocted: set up their classmates by triggering Simon’s severe peanut allergy, and have someone save him at the last minute with an epi pen from the nurse’s office. The plan went awry, however, when Jake got paranoid about Simon recording their conversations on his Xbox. Not wanting the prank to be traced back to him — and seeing the opportunity to frame his cheating girlfriend, Addy, for murder — Jake stole the epi pens from the nurse’s office, leading to Simon’s death. 

The five people in detention were the only ones with access to the peanut oil-laced water Simon drank, which pointed to one or all of the Bayview Four being responsible, but it turned out that Simon tainted his own water. Suicide was ruled out when the nurse’s office had record of Simon bringing more epi pens in just that morning to ensure someone would be able to save him. Jake was responsible for stealing the epi pens and taking over Simon’s gossip app, About That, after his death.

Addy stands in front of Jake's screen with proof of Simon's chats projecting onto her face on One of Us Is Lying

(Image credit: Peacock)

How Did The Bayview Four Solve The Murder? 

After the Murder Club learned why the police had ruled out suicide, it was clear Simon had been working with somebody. Addy became suspicious when she recognized Simon's handle in Jake’s Xbox chat history. They also realized that Jake had access to Bronwyn’s backpack that day to plant the cellphone that got her detention, as well as Addy’s backpack to set the alarm that got her in trouble, and Jake had taken Simon’s Xbox after his death.

Jake pulls a gun at the Halloween party in One of Us Is Lying

(Image credit: Peacock)

What Happened To Jake?

Jake caught the Murder Club trying to steal Simon’s Xbox that they rightly assumed had evidence of Jake’s involvement. Jake pulled a gun on them as Addy escaped with the Xbox into the woods with Jake chasing her. Cooper and Janae followed, and Janae hit Jake with a bat, causing him to drop the gun. The four of them scrambled for the gun and — naturally — a gunshot rang out, revealing that Jake had been shot (but by whom?). The now-actual Murder Club disposed of Jake’s body, and made it look like he fled the country when the truth was revealed about what he did to Simon.

Bronwyn walks through the cafeteria in One of Us Is Lying.

(Image credit: Peacock)

What Were The Bayview Four Hiding?

They may not have started out as murderers, but each one of the Bayview Four was definitely lying, and Simon had been ready to expose them on About That, giving each of them motive for murder. Bronwyn stole a chemistry test to raise her grade. She also threatened Simon after she learned that he had sexy photos of her sister, Maeve. 

Cooper’s secret was that he was gay, but Janae changed the post to falsely accuse the baseball player of taking steroids, because she didn’t want to out him. It was also revealed that Cooper had been involved in an altercation with the brother of a guy he was seeing in Mississippi, which forced his family to relocate to Bayview. 

Addy’s secret was that she’d cheated on Jake with TJ. And Nate sold drugs to Janae, which almost caused her to overdose. And, though it didn’t come out on About That, Simon had hinted that he knew Nate’s mother was still alive, even though Nate told everyone she was dead.

Janae in One of Us Is Lying

(Image credit: Peacock)

How Were Janae And Maeve Involved?

Simon’s best friend, Janae, released the Bayview Four’s secrets on About That following Simon’s death because she assumed one of them was guilty and wanted to show motive. But, when someone locked her out of the app and changed the password, she realized the murderer was not one of the Bayview Four, and she joined in their investigation.

Maeve — Bronwyn’s sister and the Murder Club’s hacker — was dating Simon, but he had ghosted her. Maeve stole Simon’s laptop to look for clues as to why he ended the relationship, but instead was able to hack into About That, and sent the hard drive to the police. 

Vanessa looks at Addy's phone on the track on One of Us Is Lying

(Image credit: Peacock)

What Secrets Did Simon Have On Vanessa And Mrs. Avery?

Through some sort-of sloppy detective work, the Bayview Four realized their detention teacher, Mrs. Avery, might have had motive to kill Simon, as she was also being blackmailed with a secret. Simon learned that Mrs. Avery had helped Addy’s frenemy Vanessa through an unplanned pregnancy and had driven her to get an abortion. In exchange for keeping her secret quiet, Simon asked Mrs. Avery to arrange for the Bayview Four to be in detention with him that day. He even set up the streakers to get her out of the room and provide her an alibi. 

Addy walks through the halls at school in One of Us Is Lying.

(Image credit: Peacock)

Why Were The Murder Club Members Not Talking At The End?

After Jake’s death in the woods, there was a two-week time jump, which revealed that, other than Jake being presumed on the lam in Tijuana, everything had gone back to how it was before Simon’s murder — i.e. the Bayview Four were not friends. That might have been for self-preservation purposes, as Annalisa Cochrane — who played Addy — told Hollywood Life

I personally think there’s a little bit to protect whatever happened in the woods that night. I think there is a little bit of a pact that everyone will just go back to their other lives, their lives before.

After the Murder Club became responsible for an actual murder, it makes sense that they’d take the advice they’d been given all along and stay away from each other. 

Maeve stands on her chair and talks during a debate in One of Us Is Lying

(Image credit: Peacock)

Will One Of Us Is Lying Return For Season 2?

One of Us Is Lying definitely left the door open for a Season 2, as Season 1 ended with the Murder Club receiving texts threatening to reveal what happened with Jake. Peacock hasn’t given official word either way yet, but if the series is renewed, there’s a chance Season 2 would be based on the events of the book’s sequel, One of Us Is Next by Karen M. McManus. The book is set one year after the events of One of Us Is Lying and centers around Maeve as someone is determined to keep Simon’s memory alive through a dark game of Truth or Dare. 

While we wait on word about another season of One of Us Is Lying, Season 1 can be streamed in full by subscribers of Peacock Premium, if you want to go back and check for clues you might have missed the first time around.  

Heidi Venable

Mom of two and hard-core '90s kid. Unprovoked, will quote Friends in any situation. Can usually be found rewatching The West Wing instead of doing anything productive.