What do you get when you sprinkle a little bit of murder into the cult classic film The Breakfast Club? A high-stakes thriller about five kids who walk into detention—and only four walk out alive. Karen M. McManus’s debut YA novel One of Us Is Lying (Delacorte, 2017) has been a staple on bestseller lists and will soon land on TV screens come October 7 on Peacock, NBCUniversal's streaming service.

The eight-episode adaptation will roll out over the course of three weeks, with new 60-minute episodes dropping in batches on Thursdays. The series stars Annalisa Cochrane as Addy, Chibuikem Uche as Cooper, Marianly Tejada as Bronwyn, Cooper van Grootel as Nate, Barrett Carnahan as Jake, Mark McKenna as Simon, Melissa Collazo as Maeve, and Jessica McLeod as Janae. Darío Madrona (co-creator of Elite) serves as showrunner and executive producer. Erica Saleh (Evil) wrote the pilot and also serves as executive producer along with John Sacchi and Matt Groesch of 5 More Minutes Productions, who developed the pilot. Filmmaker and actor Jennifer Morrison directed and produced the pilot.

Talks about film rights began before the book published. “My film agent was having conversations with producers,” McManus recalled. She described the long journey the book took to make it onto screen, including two years of script development, and the delays that Covid put on production in late 2019 until filming picked back up in April 2021 in New Zealand.

Serving as a consultant on set, McManus wasn’t directly involved in the creative direction or outlining the series but was able to view scripts and provide feedback. However, her intimate knowledge of the One of Us Is Lying world was a valuable resource for Saleh in adapting the book from page to screen. “She was a great collaborator and allowed some new ideas into the project,” Saleh said. “She has all sort of ideas and knowledge that didn’t make it into the book, so being able to call her and say, ‘Hey, this is something we’ve been thinking about, did you have any ideas about this?’ was really awesome.”

As with any adaptation, not everything can make it into the final product, but the team behind the TV series was determined to keep it as close to the original source material as possible. “I had given the producers a list of what I considered iconic moments [that] I personally loved and that I knew readers loved too,” McManus said. “They couldn’t use all of them... [but] I’ve seen rough cuts of them and I think readers are really going to enjoy watching it.”

Fans of the book can look forward to more backstory on the beloved characters, including the origins of the gossip app About That and its creator, Simon. McManus expressed excitement about a particular romantic scene between Nate and Bronwyn. “Super fans will know exactly what I mean.” For her part, Saleh can’t wait for audiences to see the bathroom scene between Addy and Janae. “You see Addy’s humanity in a different way. You see Janae’s humanity in a different way, and just that little suggestion of understanding between those two.”

One bright side to the production’s long Covid-induced delay, Saleh said, is that in the interim the actors all reread the book “and had even more to say about their characters. That’s a little bright side about how long it took.”

Seeing their hard work pay off has been immensely gratifying. Marino said, “I just sent Karen a picture: they’re advertising it on the sides of buses in New York right now and as my assistant said, ‘This is a Sex in the City moment.’ ”

When asked what she hopes the audience connects with, Marino said, “The thing that I love about this novel and that I think that Karen does well: it’s a group of people from different cliques who find the things that they have in common and become allies. [It’s] finding that commonality between people that are different from you and connecting to them.”

“Ultimately I hope that readers enjoy seeing a story that they love unfold in a new way,” McManus said.

Fans can follow the official Instagram @oneofusislyingpeacock or see the cast at a panel at New York Comic Con. McManus’s voracious fans will be pleased to know that a novel with a killer twist on a classic ’80s movie is coming out in November, along with the hint of a new movie. “There’s film stuff I can’t really talk about right now,” she said, “but I do have my fifth book coming out in November, which is You’ll Be the Death of Me, and that is like Ferris Bueller’s Day Off meets a murder mystery.” McManus also has two more books in the works: the final installment of her One of Us trilogy, One of Us Is Back, due in 2022, and a standalone YA mystery coming out in 2023.