You'll Be the Death of Me author Karen M. McManus reveals how she puts thrilling tales together

For Karen M. McManus, You'll Be the Death of Me began as a kernel of an idea in 2017. Four years later, the YA thriller is ready for readers to dive into. Hitting shelves Nov. 30, the book follows childhood friends Cal, Ivy, and Mateo as they skip school together in spite of their fractured ties and stumble onto a dead body. The story takes place over the course of the day as they try to get to the bottom of the crime and deal with their own secrets along the way.

One of the strengths of the new book is its ensemble, who have to function as team despite their strained relationships. "I spend a lot of time thinking through the group dynamic and making sure the characters have points of view, connection, conflict and chemistry," McManus tells EW.

Ivy is an overachiever, Cal is a bit of an outsider, and Mateo strives to always be responsible, so in many ways they complement one another. At the same time, their former friendships and current predicament provide challenges that will set up their meaningful growth.

Between You'll Be the Death of Me and the One of Us book series, which has been adapted for TV with Peacock's One of Us Is Lying, McManus has a proven track record of delivering page-turners. Below, she shares three key elements that make her thrillers so hard to put down.

1. Compelling characters for readers to care about

For McManus, creating characters means having their fears, wants, and needs work within and outside the central mystery. The relatability of characters' flaws in the One of Us series is something she often hears about from readers. In the first installment of the series, One of Us Is Lying, their flaws are the reasons they all end up in detention, and they cannot allow those flaws to get in their way because to solve the mystery, they need to deal with the issues in their own lives.

Readers' ability to relate is what gets them to root for characters, and One of Us Is Lying's Addy is a perfect example. While she's the character McManus hears about most from readers, the author was initially worried readers wouldn't give her a chance and would get impatient because of her flaws. "It's been really gratifying to see how she's been embraced and people share the journey she goes through, starting to understand herself and what she's worth," McManus says.

With You'll Be the Death of Me, McManus highlights Ivy, who is "annoying in the beginning and maybe a little annoying throughout." Her pettiness and inability to let go of things contribute to Ivy being in the mess she finds herself in. "What [Ivy] goes through and the realization that so much could have been avoided with some well-timed conversations help her get to a better place by the end," McManus teases.

2. Ever-escalating tension

A story's tension needs to be build and peak at "the right moment," McManus says. One way she achieves this is by introducing several sub-mysteries. In her new book, all the main characters have secrets. "Some of them relate to what ended their friendship in the past, and some relate to the current situation," she says. "My job is to figure out what to reveal when." Cal's secret is the first one revealed because it helps kick off the mystery, and Ivy's is last because it affects the relationships that evolve throughout the book.

Part of the equation for a McManus thriller is that relationships and plot tension are equally important. She notes that readers were passionate about the connection between Nate and Bronwyn in One of Us Is Lying, and her latest offering will also offer romantic and friendship subplots. "It can be romantic, it can be platonic, it can be familial, but you want your reader to be invested in how these characters connect," McManus says.

3. A satisfying — and hopefully surprising — reveal

The art of the reveal is another crucial element of a strong thriller. "I don't think the success of a thriller should lay entirely on whether or not readers are able to get the ending, because someone's always going to guess," McManus says. "I never want my endings to feel as though they're coming out of the blue, but I hope that you have a hand-to-the-forehead moment where you think, 'How did I miss that?'"

The twists in One of Us Is Next are a prime example. There's a pretty straightforward reveal that "seasoned mystery readers probably saw coming," McManus says, but it hid a twist at the very end to keep readers guessing. "Part of the reason they missed it possibly is because they were solving the first reveal," she says, "so I like doing that kind of thing."

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