Five students—strangers to each other—walk into detention at Bayview High: the brain, the beauty, the jock, the criminal, and the outcast. This is the set-up for One of Us Is Lying (Delacorte, May), the debut YA novel by Karen M. McManus, which has been on the New York Times bestseller list for five weeks straight, and currently sits in the #2 spot. And, if the book’s premise sounds familiar, that’s because it purposely echoes the opening notes of the classic 1985 John Hughes movie The Breakfast Club. But many of those initial similarities fade away when McManus’s tale takes a much darker turn, and only four of the five students leave detention alive. Those remaining are obvious suspects, and they all are keeping secrets.

“I actually got the idea while I was driving and listening to the radio,” McManus said, noting that she gets lots of ideas that way. “I think there’s something about having half my brain engaged in a mundane task that kind of gives the other half freedom to roam.” During her drive, the song “Don’t You (Forget About Me)” by Simple Minds from the Breakfast Club soundtrack came on. “I started thinking it would be fun to write an update of that movie, which I loved, but with some sort of a twist,” she said. “And the phrase ‘The Breakfast Club with murder’ popped into my head and it just stuck there.”

She “noodled” on the idea for a while imagining how, and just as importantly, why, you would kill somebody in a classroom. With those questions settled, “the four characters started springing into my mind and just sort of took off from there.”

And “took off” is the right phrase to describe One of Us Is Lying’s performance thus far. To date the book boasts 120,000 copies in print and rights have been sold into 20 territories.

When it comes to puzzling out what the hook for her book has been, McManus has heard feedback that “it’s the characters. In some way it’s maybe helpful to have four of them because almost anybody can connect with someone,” she said. “[Readers] feel that the characters are relatable and appreciate that they are all flawed. The characters all have growth arcs, and go on different types of journeys to end up in a different place from where they started the book. So they feel real.”

Krista Marino, executive editor at Delacorte Press, agrees with that assessment. “Something about this book feels very authentic,” she said. “People might pick it up because it seems like it’s Breakfast Club meets Pretty Little Liars, but then you read it, and it’s grounded in the real world. The characters are not flashy Hollywood kids and this is a real situation that could happen.” Beyond character development, Marino lauds what she sees as the book’s other points of appeal. “It’s such an easy, fast read and so compelling in so many different ways,” she said. “It’s easy to talk about and pitch, which is a blessing for publishers, but it exceeds your expectations.” She has received feedback that the cover is very compelling to readers, which, she said, “is nice to hear.”

The novel’s “realness” has so far been a draw for both guys and girls, as well as for adult readers. McManus has heard anecdotally that parents are reading the book and discussing it with their kids, and that kids are discussing it with each other, as a sort of cautionary tale about the dangers of social media getting out of control. “It’s almost an education to parents, if they’re reading it as well,” said Marino, “because so much of what happens online is invisible to them.”

McManus, a self-described fast writer, began working on One of Us Is Lying in fall 2015. It was her third attempt at a YA novel and it represented a return to her lifelong love of writing after a considerable break. She had started writing at an early age and “I told everyone I was going to be an author,” she recalled. But, when she floundered trying to write novel-length fiction in high school, she set her passion aside. “I went to college, got a job, started a family—all wonderful stuff,” she said, “but I took a lengthy hiatus before I tried again.” Her inspiration for giving it another go came when she read the Hunger Games trilogy by Suzanne Collins. “Something about that young adult voice spoke to me and made me want to try creating a world again,” McManus said. “My first book was a terrible dystopian knockoff, but it got me back into writing, and I finished it. So, I realized ‘I can do this!’ ”

The other thing that was different about McManus’s journey back to novel writing was discovering a community of kindred spirits. “I started connecting with other writers via social media,” she said. “That’s really what had been missing for me before. I didn’t know anyone else who wrote and when it got hard there was no one to tell me, ‘just get it down, you can fix it later,’ or to exchange work with, so I could recognize flaws in my own. That was huge for me. I just loved it. I would have done it whether or not I ever sold a book, and I just kept doing it and eventually got to the book that worked.”

By January 2016, McManus was ready to send One of Us Is Lying out for query, and literary agent Rosemary Stimola at Stimola Literary Studio (who also represents Suzanne Collins) was one of the first recipients. Stimola requested the manuscript immediately, and offered McManus representation about a week later. Stimola kept things on the fast track by submitting the book to Marino right away. “I believe we bought the book in about a week,” Marino said. She signed McManus to a six-figure, two-book deal in March 2016, preempting North American rights.

Prior to the book’s publication, early readers of the ARC, which was given away at various teen book festivals, created online buzz for the title. A social media ad campaign reaching the teen audience followed, featuring lifestyle photography. As early as January, the novel was named to several “most anticipated” book lists from such online and print outlets as Entertainment Weekly and the B&N Teen Blog. Positive reviews appeared in trade journals as well as in national print and online publications, and the book was featured by booktubers on YouTube during the month of June. One of Us Is Lying received feature treatment via Penguin Random House’s social media channels and recently launched site, where visitors can post responses to the book, take quizzes related to the story and characters, and find other books in the same category. Throughout the month of July, Penguin Random House’s larger “I Know What You Read Last Summer” campaign targeted teens and adult mystery/thriller fans, and among its suggested titles was One of Us Is Lying. An Instagram tour ran between May 28 and June 3, and a blog tour for the book dovetailed with that effort, running May 29 through June 16.

McManus appeared at a launch event at Porter Square Books in her hometown of Cambridge, Mass., and had several promotional meetings at Waterstone’s stores in the U.K. in late July. Fall events include the Boston Teen Author Festival on September 23, and two visits for which she is teaming up with fellow debut author Tara Goedjen (The Breathless, Delacorte, Oct.): Boswell Books in Milwaukee on October 17 and Red Balloon Bookshop in St. Paul on October 19.

“Now it’s just building on itself,” said Marino, speaking about all the positive attention for the book. “You usually see that kind of buzz quiet down after publication, but it’s only gotten louder and louder. To me that said that people are connecting with the characters and feeling satisfied. I think it goes far toward the popularity of a story if you have a lot to talk about after reading it.”

Marino calls all this initial success “so refreshing,” noting that in the book-publishing arena, “It’s been a tough market all around. There are so many books that are so wonderful that get overlooked. To have a book exceed our high expectations and just be a natural, organic success—it’s a happy surprise. I only wish it happened more.”

McManus said she’s “pretty far along” on her second YA novel, a standalone “in the suspense/thriller vein,” tentatively scheduled for fall 2018. And in the meantime, she’s letting the excitement of her debut soak in. “When you put a book out there, it’s your best work, you’re happy with it, you’re proud,” she said. “But you have no idea how anyone else is going to feel about it. For people to connect with it and come to care about the characters the way that I do has been really gratifying. I’m so thrilled and grateful.”