New York, New York - Author Nina Simon returns this month with the can't-miss thriller My Sister Is Going to Kill Me, and in an exclusive chat with TAG24 NEWS, she dished on the inspiration behind her latest release.

My Sister Is Going to Kill Me, which hits bookstores on August 18, follows two very different sisters: straight-laced State Department analyst Liv and the "bedazzled human tumbleweed" that is Mandy.

The novel follows their annual sisters' trip, which this year takes them into the depths of the Grand Canyon on a rafting adventure.

But soon, Liv and Mandy find themselves entrenched in a mystery after someone winds up dead – and everyone is suspect.

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"In most mysteries, you have a dead body almost right away within the first three chapters. And that is not the case in My Sister is Going to Kill Me," Simon told TAG24.

"I needed them to get far enough in the trip that they couldn't just bail. If there was a dead body right at the beginning when they're hiking down to start the rafting, they would just never go rafting."

And so, Liv and Mandy find themselves desperate to solve the mystery – and they're not alone. The rafting adventure is also tied to a new product launch from a buzzy, "Goop-esque" skincare company, and the complicated dynamics between the guests just might hold the answers to solving the deadly case.

Simon drew inspiration from her own rafting trip with her sister, where they had the chance to decompress from the pressures of life as caregivers for their parents and, as Simon described it, could enter a new environment "just as the sisters."

"I really want to explore this question of, as we've grown up and maybe grown apart, how do siblings come together, not just because we are related, but because we are deeply connected to each other and deeply love each other?" Simon explained.

Liv and Mandy aren't quite as close as Simon and her sister, and while the characters differ significantly from their real-life relationship, the author said there are "definitely pieces of both of us in each of them."

"I had fun writing these two sisters in a way that was very different from each other, but where they each had credible skills they could bring to a murder investigation conducted with no support out in the wilderness, all on their own," Simon added.

Simon burst onto the literary scene with Mother-Daughter Murder Night, another family-focused murder mystery filled with plenty of heart. The novel was selected as a Reese's Book Club pick in September 2023 and became a New York Times bestseller.

But as Simon told TAG24, she never expected to become a full-time author.

"I wrote it really never expecting it to be published," she explained. "I wrote it while my mom was going through very intense cancer treatment, just as a way for her and I to connect and to find some escape and something joyful together during that really hard time."

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As she continued to lean into her new career as an author following the success of her first novel, Simon knew she wanted to stay in her favorite lane – one filled with "strong women, wild places, and dead bodies."

But despite the sometimes dark subject matter, Simon has kept a deep focus on the relationships at the heart of the stories.

"I would say that in general, when I'm thinking about writing and mysteries that really inspire me, it tends to be mysteries that have deep characterization, gorgeous prose, and sometimes a real dash of humor in it," she said.

Though she's become a master at crafting the perfect plot twist, Simon said that her goal is never perfection. Instead, she lives by a sign she keeps over her writing table that reminds her the aim is always "a fun, heart-filled story."

"And I feel like that's what I'm trying to do – to write with love, to write with warmth, to write with energy."

As for what Simon will dive into in her next novel, she gave TAG24 quite the teaser: "It's multigenerational, and it's about two women from very different backgrounds and very different ages, who come together to seek justice for another young woman who died."

And as if My Sister Is Going to Kill Me's Grand Canyon setting wasn't thrilling enough, Simon revealed that she plans to set the new story in the Southwest amidst a freight-train-hopping adventure.

Craving more of this summer's hottest new reads? Catch up on all of the latest literary drops with TAG24's Book Release Radars for June and July 2026.