So, you’ve probably seen the covers. They’re everywhere on BookTok and in the YA sections of every local shop—stark, moody imagery of puzzles, blood-red accents, and that familiar typeface. Jennifer Lynn Barnes has a knack for writing "smart" thrillers, but before she took over the world with The Inheritance Games, there was a smaller, grittier, and frankly more intense series that hooked a generation of mystery lovers. If you’re trying to figure out the Naturals series in order, you aren't just looking for a list of titles. You’re looking for a roadmap through a world of forensic profiling, teenage prodigies, and some genuinely disturbing cold cases.
It's a wild ride. Honestly, reading these in the wrong order would be a total disaster because the overarching mystery regarding Cassie’s past is a slow burn that relies heavily on character development.
Where It All Begins: The Core Four Books
You have to start with the book that launched it all.
The Naturals (2013) introduces us to Cassie Hobbes. She isn’t a psychic—let's get that straight right now. She’s a "natural" at reading people. She sees the tiny details that most people miss: the way a person’s eyes dart when they lie, the subtle shift in posture that signals aggression, the minute traces of a person's history written on their face. This isn't magic; it’s observation dialed up to eleven. When the FBI recruits her for a classified program involving other gifted teens, she thinks she’s finally found a place to belong. But then a serial killer starts leaving her personal messages. It's dark. It's fast. It sets the stakes immediately.
Then comes Killer Instinct (2014). This is where the group dynamic really starts to gel. While the first book focused on Cassie, the sequel dives deeper into the rest of the team. You have Dean, the son of a notorious serial killer; Michael, who can read emotions; Sloane, the human calculator; and Lia, the human lie detector. They're tasked with helping the FBI solve a new series of murders that feel eerily similar to cases from the past. Barnes does a great job here of showing the psychological toll this work takes on teenagers who aren't even old enough to vote yet.
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All In (2015) takes the team to Las Vegas. If you like high-stakes gambling and neon-lit crime scenes, this is your peak. This book focuses heavily on Sloane’s backstory. She’s often the comic relief because of her obsession with statistics and her social awkwardness, but All In shows the trauma behind the numbers. It’s also where the romantic tensions—the classic Dean vs. Michael debate—really start to boil over. Some readers find the love triangle annoying, but Barnes handles it with more nuance than your average YA trope.
The final full-length novel is Bad Blood (2016). This is the big one. This is where every thread Barnes has been dangling since page one of the first book finally gets pulled. We finally get answers about Cassie’s mother and the cult-like organization that has been lurking in the shadows. It’s a massive payoff. If you’ve made it this far, you’ll probably finish this 400-page book in a single sitting. I’m not kidding. The pacing is relentless.
Don't Forget the "Point" (The Novella Problem)
A lot of people miss the bridge between the third and fourth books.
Twelve is a novella that technically fits between All In and Bad Blood. While you can understand the main plot without it, it provides crucial context for what happens in the finale. It’s short, punchy, and gives you a glimpse into a case that happened a year before Cassie joined the program. It’s basically the "origin story" for the team as a unit. If you're a completionist, do not skip this.
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Why the Order Matters More Than You Think
You might think, "It’s a procedural, I can jump in anywhere."
Wrong.
Unlike Law & Order where every episode is a fresh start, The Naturals is a serialized narrative. The FBI’s "Natural" program is under constant scrutiny from the higher-ups. If you read Bad Blood first, you’ve essentially spoiled the three-year mystery of who killed Cassie’s mom. That’s the emotional heartbeat of the series. Plus, the evolution of Dean and Michael’s friendship—and their rivalry for Cassie’s affection—makes zero sense if you skip the middle chapters.
The Science of Profiling: Facts vs. Fiction
Jennifer Lynn Barnes actually has a Ph.D. in developmental psychology. This is why the series feels "smarter" than some other YA thrillers. When Cassie talks about "micro-expressions" or "behavioral clusters," it’s rooted in real-world psychological theories popularized by experts like Paul Ekman.
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However, we have to be realistic here. The FBI does not actually have a secret program where they let seventeen-year-olds live in a mansion and solve active serial killer cases. The real Behavioral Analysis Unit (BAU) in Quantico is made up of seasoned professionals with decades of experience. The "Natural" aspect of the series is a heightened, fictionalized version of real intuitive abilities. It's important to enjoy the series as a "what if" scenario rather than a textbook on forensic science.
Reading Order Summary
- The Naturals
- Killer Instinct
- All In
- Twelve (Novella)
- Bad Blood
What Most People Get Wrong About the Ending
There’s a common misconception that the series ends on a cliffhanger. It doesn't. Bad Blood provides a very definitive conclusion to the main arc. However, there is a lot of "fan-service" demand for a fifth book. Barnes has moved on to other massive projects like The Brothers Hawthorne, but she has never explicitly ruled out returning to this world.
The ending of Bad Blood is bittersweet. It acknowledges that these kids can never really go back to being normal. They’ve seen too much. They know too much. The series is as much a coming-of-age story as it is a crime thriller. They grow up, but they grow up in the dark.
Actionable Next Steps for New Readers
If you're ready to dive in, don't just buy the first one. Most readers find that once they finish the first book, they need the second one immediately. Look for the boxed set or the bind-up editions that often include the novella.
- Check the copyright dates: Some international editions have different titles or covers. Stick to the publication order listed above to ensure you don't spoil the major twists.
- Keep a notepad: This sounds nerdy, but the "puzzles" in the books are actually solvable if you pay close attention to the clues Barnes drops. It makes the experience way more interactive.
- Check out the "The Inheritance Games" afterward: If you finish the series and have a Barnes-shaped hole in your heart, her newer series carries over the same "genius kids solving impossible puzzles" vibe, though with a bit more of a "Cinderella" twist.
The series is a masterclass in tension. It manages to be clean enough for a YA audience while being dark enough to satisfy seasoned true-crime fans. Start with the first book, pay attention to the "tells," and try to out-profile the profilers. You’ll see why it’s stayed relevant for over a decade.