How I Came Up With the Idea for Under the Surface

The story behind the romantic survival thriller set in the Paris catacombs... inspired by true events.

Under the Surface is a thrilling survival story about a girl who goes missing in the Paris catacombs for days, while aboveground the boy she loves races to find her and a media frenzy begins. People ask me how I came up with this idea all the time, so today I’ll share this book’s origin story… and how it was inspired by true events.

Before we dive in, I quickly want to share the news that Under the Surface’s paperback edition will be out on May 27, 2025, with lovely purple edges (AHHHHHHH!) and a catacombs map, and it’s 25% off on Barnes & Noble until February 7. Hooray!

It started with a love of survival stories…

I’ve gobbled up as many survival stories as I could find over the years, starting in middle school with Hatchet by Gary Paulsen. It’s about a boy who survives a single-engine plane crash and finds himself alone in the middle of the woods, and it made me wonder if I’d be resourceful and brave enough to make it out alive, or if I’d curl up in the fetal position until a bear sniffed me out. Let’s be real—probably the latter.

Then in high school I came across Alive by Piers Paul Read, a real-life account of a Uruguayan rugby team that crash landed in the Andes in the 1970s, which I read way too many times considering all the cannibalism. Yeah. 😬 Those poor people.

Over the years I continued to seek out survival thrillers, whether contemporary fiction like Hatchet, stories inspired by true events like Alive and Apollo 13, sci-fi like The Martian, dystopians like Bird Box, or video games like The Last of Us.

There’s something so damn compelling about people enduring in the face of impossible odds. For a long time, I knew I wanted to write a survival story of my own. I just didn’t know what that would look like.

2015: The idea takes shape

I first visited the Paris catacombs in 2015. In case you’re not familiar with the catacombs, here’s a small excerpt from Under the Surface when our protagonist Ruby meets Julien, an alluring Parisian boy who takes her and three friends underground. She explains:

We’ve been dying to see the catacombs—the intricate web of tunnels beneath the city where the skeletal remains of six million long-dead Parisians line miles and miles of passageways in artistic arrangements. It has to be one of the creepiest things you can see on the entire planet, which obviously means I have to see it. Mr. LeBrecque added it to our itinerary after I begged and pleaded, but we’d be visiting the small touristy section—the only bit open to the public. Most of the other entrances scattered throughout Paris have been sealed for ages, and the only accessible ones are secret from everyone except for—

“You’re a cataphile, aren’t you?” I ask Julien, breathless. Suddenly his outfit makes sense.

Selena sputters a laugh. “Did you just call him a pedophile?”

“A cataphile,” Olivia pipes up. “It’s what they call the explorers who meet up in the catacombs.” Of course she’d know about them, too. “Illegally, I might add. Isn’t it dangerous down there?”

“How’s it dangerous?” Selena asks.

“It’s not if you know what you’re doing,” says Julien, “and where you’re going. And I do.”

Unlike Ruby, who agrees to go to Julien’s party in a restricted area, I only explored the small section open to the public, where locked gates block any tunnels leading away from the official tour route, preventing you from getting lost.

Still, I was nervous. Spiral staircases trigger my claustrophobia; when I previously climbed the domes of St. Peter’s Basilica in the Vatican City and St. Paul’s Cathedral in London, I was a sweaty, shaky, out-of-breath, panicked mess. And to reach the catacombs, you need to descend a 131-step-deep spiral staircase. 😱

I almost chicken out, honestly. But I wanted to see those ancient tunnels so badly, I braced myself and took the plunge. Counting each step helped me focus on something besides THESE STAIRS WILL NEVER END and I’M GONNA FALL AND DIEEEEEE. My legs shook like a leaf, but I made it to the bottom in one piece—sans panic attack.

Our tour guide explained that the underground tunnels span 300km underneath much of Paris, a labyrinth that originated as limestone quarries in the 12th century. In the 1700s, entire city streets collapsed into the old abandoned tunnels, launching a fortification project. Around the same time, Paris’s cemeteries were overflowing into neighboring basements during heavy rainstorms. This was obviously a major health hazard—and disturbing AF—so city officials decided to relocate six million corpses into the catacombs. Fortification workers took great care organizing the bones using their standard methods: small rocks (er, bones) piled in the back, with bigger pieces like skulls, femurs, and tibias up front, which they arranged in artistic patterns.

Today, the ossuaries you can tour are only a small part of the vast network of tunnels. The rest is illegal to enter because it’s too dangerous; cave-ins, flooding, and other obstacles have caused explorers to get lost. In fact, throughout the centuries, scammers would pose as tour guides to lure their marks into the dark maze, then would rob and abandon them to find their way out alone.

AND THERE IT WAS. The anecdote that sparked the idea for Under the Surface.

My brain started whirring with ideas, right there in the catacombs. What a terrifying story it would be if someone in modern times got lost in that pitch-black maze with only a flashlight, its battery like a ticking timer. And what a heart-wrenching romance it would make, if a couple falling in love got torn apart when she gets lost in the catacombs and he’s aboveground racing to find her.

2017-2018: Inspired by the news

This idea floated around in my brain for years, but I was a new writer at the time and didn’t feel ready to tackle something so weighty—I wanted it to be this epic survival story that would make people sob. So I wrote another manuscript that ended up getting shelved, then All Your Twisted Secrets, which wound up being my debut.

But every so often, I researched a little more about the catacombs, watched YouTubers’ first-hand experiences, noted down interesting facts. I learned more about cataphiles, the urban explorers who play cat-and-mouse with the police to open sealed entrances to roam, graffiti, and party in the tunnels.

Then, in June 2017, I saw a news story about teenagers who were rescued from the Paris catacombs after being lost for three days.

This story didn’t gain much traction, and if you try to research it, you won’t find much. I never attempted to reach out to the parties involved; their experience was, I’m sure, quite harrowing, and I hope they’ve made a full recovery in peace. But seeing this story validated my premise—it’s realistic even in modern times.

Another year passed while I signed with an agent for All Your Twisted Secrets, completed an R&R for a publisher, and landed my first book deal.

Then, in June 2018, a junior football team in Thailand got trapped in a flooded cave for 12 days. This time, the news coverage was swift and monumental, and it became a global phenomenon as the world watched the boys get rescued.

Seeing the media’s reaction on a global scale was also validating; I’d always envisioned Sean’s POV showing the rescue efforts aboveground and the ensuing media frenzy. This finally compelled me to email the pitch for Under the Surface to my agent.

2019: Back to the catacombs for research

My agent loved the idea right away. But contractually, my publisher wasn’t obligated to consider my next proposal until All Your Twisted Secrets was accepted for copyedits, and that was a ways off. But I was determined for this to be my next book, so in 2019 I headed back to Paris and down into the catacombs for some real research.

These pictures are from this 2019 trip:

I also explored the area surrounding the Luxembourg gardens and found a street corner I visualized as the spot where Ruby, Selena, and Olivia meet up with Val and Julien in chapter four.

I took loads of pictures and diligent notes of my tour guide’s anecdotes—and he was an actual cataphile. After this trip, I wrote a proposal for Under the Surface: the opening three chapters and a synopsis.

A long road to publication

This essay is about how I got the idea for Under the Surface, not about the messy innards of the publishing industry. But it took another five years to get this book published, and I want to show you why. Here’s what happened next:

• November 2019: My agent submitted the proposal to my first publisher, but they wanted to wait until All Your Twisted Secrets launched in March 2020 to gauge its performance. This relinquished their first right of refusal (aka my option clause). This same month, I wrote a very messy first draft for NaNoWriMo.

• November 2019: I didn’t want to wait until my debut published to sell another book, so my agent took the proposal out on submission to other publishers. In the meantime, I started working on a proposal for These Deadly Games.

• Over the next few months, rejections rolled in. One actual quote: “We think this should be pushed more as a thriller and less as a thriller/romance.” Editors didn’t want Sean’s secondary POV. I wasn’t willing to publish the book without it. Sean is half of the love story, and his aboveground chapters give readers the occasional reprieve from the catacombs. The book would feel too claustrophobic without him.

• March 12, 2020: The pandemic hit. Shelter in place began.

• March 17, 2020: All Your Twisted Secrets was released. Bookstores were closed and Amazon only shipped essential goods that week, not including books. This massively impacted my first-week hardcover sales. It still technically had the numbers to hit the New York Times bestseller list but was curated off. Despite this, AYTS went to a second printing within two weeks and earned out within three months, and ebook sales were high for a YA book. I’m so grateful to readers for this.

• April 2020: My first publisher officially declined to buy another book from me because “sales of All Your Twisted Secrets weren’t as high as we hoped.” They wanted a bestseller, I guess. Sorry a pandemic happened, I guess.

• April 2020: My agent took my new proposal for These Deadly Games out on submission. It sold two weeks later to Macmillan.

• 2021: Penguin Random House (PRH) signed me for Lying in the Deep.

• 2022: My editor at PRH bought Under the Surface! Hooray! I finally got to start drafting it in earnest, scrapping most of my NaNoWriMo draft.

• 2023: I rewrote the book twice more during developmental edits. Whew.

• August 13, 2024: Under the Surface released!

Writing and publishing this book was one hell of a journey. But I’m so excited it’s finally out in the world, and I’m so proud it was an instant indie bestseller, selected for the Indie Next List and Junior Library Guild, and an Amazon best book of 2024. 🥹 If you’d like a copy, here’s where you can get one—the hardcover, ebook, and audiobook are out now, and the paperback comes out 5.27.25!

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