The Naturals series guide
The Naturals Books in Order: What to Read Before Dangerous Impulses
Four original novels, one future-set novella and a fifth novel arriving in 2026. Where Twelve fits, and what the different editions contain.
The reading order
Start with the four original novels; treat Twelve separately
Publication order is The Naturals, Killer Instinct, All In, Bad Blood, Twelve, then Dangerous Impulses. Twelve is a novella set later in Cassie's life, not the fifth main novel. Dangerous Impulses is book five, scheduled for November 3, 2026 in the US. Reading it after Bad Blood and saving Twelve for afterward keeps the main storyline together; publication order remains another route.
Cassie Hobbes can infer a stranger's habits and motives from details other people overlook. The FBI recruits her into a program for teenagers with unusual investigative abilities. Solving a case means interpreting evidence, but also working out which of the people around her can be trusted.
The series combines serial-killer investigations with the close, volatile relationships of a group living and training together. Its characters are young; its crimes involve violence, coercion and lasting psychological harm. The descriptions below explain the different cases without identifying killers or revealing how the original arc ends.
Publication order and the timeline are different
The first four novels appeared from 2013 to 2016, followed by Twelve in 2017. Dangerous Impulses returns to the main sequence in 2026. As of October 22, four main novels are published and a fifth is forthcoming. Counting Twelve adds a shorter companion work, not another full-length novel.
Twelve finds Cassie at twenty-three, several years beyond her introduction as a seventeen-year-old. Dangerous Impulses instead begins eight months after the traumatic case in Bad Blood. Publication order therefore jumps forward with the novella before returning to an earlier point with book five.
Reading Twelve after Bad Blood follows the original release sequence. Leaving it until after Dangerous Impulses avoids that jump and postpones its glimpses of the characters' later lives. The two routes preserve different things: publication history or narrative continuity. The novella is supplementary; it is not a required bridge into the fifth novel.
The published sequence
The Naturals in publication order
The years refer to the works' original publication, rather than later covers or reissues. Dangerous Impulses is the forthcoming fifth main novel.
| Publication order | Title | Year | Place in the series |
|---|---|---|---|
| 1 | The Naturals | 2013 | Main novel 1 |
| 2 | Killer Instinct | 2014 | Main novel 2 |
| 3 | All In | 2015 | Main novel 3, by Jennifer Lynn Barnes |
| 4 | Bad Blood | 2016 | Main novel 4 |
| 5 | Twelve | 2017 | Future-set novella; can be saved until after book five |
| 6 | Dangerous Impulses | 2026 | Main novel 5; follows Bad Blood in the timeline |
The books and editions
What changes from one investigation to the next?
The cases change, while personal histories and relationships carry forward. The first four novels establish the team and the consequences that Dangerous Impulses returns to.
The four original novels
These form a continuous arc. Each case makes the boundary between the Naturals' work and their private lives harder to maintain.
Main novel 1 - 2013
The Naturals
Cassie joins the FBI's teenage profiling program
At seventeen, Cassie Hobbes reads small signs of behavior almost instinctively. Recruitment into the FBI's Naturals program gives that ability a purpose: helping investigate unresolved murders. Living with the other recruits is another kind of puzzle. Dean profiles people too, Michael reads emotions, Lia detects deception and Sloane works with numbers and probabilities. Their skills overlap enough to create friction without making them interchangeable.
A new killer brings danger closer than the distant cold cases Cassie expected. The premise puts two sorts of interpretation beside each other: understanding a criminal and understanding someone whose attention might be affection, manipulation or both. Training, suspicion and romantic tension share the same space. This is the starting point for the team's relationships, as well as the first investigation.
Main novel 2 - 2014
Killer Instinct
A copycat case reaches into Dean's past
The hope of working safely on old files does not last. A new series of killings imitates a murderer tied to Dean's family history, pulling the Naturals into an active investigation. His knowledge can help explain the pattern, but the case also forces him toward a past he wants distance from. The person with the most useful insight is also the one the investigation can hurt most directly.
That changes the pressure on Cassie and the group. Their task is no longer simply to recognize a killer's habits; it is to use deeply personal knowledge without treating a teammate as another case file. The relationships established in The Naturals now complicate professional trust. Profiling becomes a source of vulnerability as well as an advantage, and the copycat problem widens the first book's conflict between insight and intrusion.
Main novel 3 - 2015
All In
Jennifer Lynn Barnes's Las Vegas investigation
Las Vegas gives the team a different problem: victims killed by different methods, public locations without useful footage of the killer, and numbers tattooed on wrists. A single recognizable method is no longer enough to connect the crimes. The numbers suggest a code, bringing the team's statistical reasoning alongside profiling and close attention to behavior.
The casino setting makes patterns, chance and calculated risk part of the investigation's language. Sloane's numerical abilities matter within a group that also needs emotional and interpersonal clues. Meanwhile, a development in Cassie's mother's case keeps the larger family mystery moving. Jennifer Lynn Barnes's All In continues those relationships and questions rather than beginning an independent mystery series.
Main novel 4 - 2016
Bad Blood
Cassie's family mystery becomes the central danger
Questions about Cassie's mother move from a private reason for joining the program to the center of a larger investigation. The team confronts a secretive group with a history extending across generations, rather than another isolated pattern of murders. Cassie's personal need for answers now sits inside a threat reaching beyond one criminal.
The distance between investigator and target narrows further: the Naturals are exposed to the people they are pursuing. That makes the case more intimate even as its scope grows. Bad Blood brings the original four-novel arc to its culmination, so its discoveries depend heavily on the earlier books. Dangerous Impulses returns to the emotional consequences afterward. Explaining exactly what Cassie learns here would spoil a central reason to follow the sequence.
Twelve: the later-life novella
Its publication slot is after Bad Blood. Its setting is further ahead, which is why it deserves its own place in the reading-order discussion.
Companion novella - 2017
Twelve
A shorter case, set when Cassie is twenty-three
A coastal Maine town, deaths treated as suicides and a twelve-year-old who insists something is wrong give this novella a more concentrated case. Cassie is an adult here. The story revisits the Naturals at a later stage, with their investigative work again tied to the difficulty of taking a traumatized child seriously.
Its shorter form offers a later glimpse of the group rather than another full-length step in the original teenage arc. Even without a summary of the outcome, that future setting can disclose things about where earlier stories lead. Reading it last preserves the forward movement from Bad Blood into Dangerous Impulses. Reading it after Bad Blood instead follows publication history. Neither route makes it the fifth main novel or required preparation for book five.
Dangerous Impulses: the fifth novel and its two editions
Eight months after the case in Bad Blood, the team is still carrying its psychological aftermath. With Christmas approaching, the Naturals attempt something more cheerful: helping their FBI mentors reconcile. Understanding what keeps Veronica Sterling from that relationship draws them into her past. Interconnected crime scenes, a killer with a fixation on snow and an unresolved case pull the personal mission back into criminal investigation. The opening premise gives the team a lighter purpose, but does not suggest their work has become harmless. The familiar abilities are now turned toward people who trained them, making this a continuation of established relationships rather than a fresh starting point.
The November 3, 2026 release
Dangerous Impulses: standard vs Deluxe Limited Edition
Both are editions of the fifth novel. The confirmed Deluxe additions concern the physical book; no extra fictional chapters are announced.
| Feature | Standard editions | Deluxe Limited Edition |
|---|---|---|
| Main work | Dangerous Impulses, main novel 5 | Dangerous Impulses, main novel 5 |
| Format | Ebook and ordinary hardcover formats; the option below is digital | Special-edition hardcover |
| Case and jacket | Ordinary edition design, varying by format | Special case design and decorative jacket effects |
| Edges and endpapers | No Deluxe physical features in the ebook | Decorated edges and special endpapers |
| Bookmark | Digital reading controls in the ebook | Ribbon bookmark |
| Confirmed extra prose | No bonus chapters announced | No bonus chapters announced |
| Edition type | Standard publication | Limited physical edition |
Main novel 5 - standard
Dangerous Impulses (Standard Edition)
November 3, 2026 - digital option
Cassie, Dean, Michael, Lia and Sloane return for an investigation that begins with matchmaking and reaches into their mentors' history. The new case follows the original arc rather than replacing it.
The digital edition contains the fifth novel without the physical decoration of the Deluxe hardcover. Its appeal is the continuation itself: the same team, earlier emotional damage and a personal project becoming another criminal problem.
Main novel 5 - deluxe
Dangerous Impulses (Deluxe Limited Edition)
November 3, 2026 - special-edition hardcover
Decorated edges, special endpapers, a distinctive case design and jacket effects extend the artwork across the physical volume. A ribbon bookmark adds a practical reading detail.
The confirmed additions are primarily visual and tactile. No bonus chapters or additional story are announced, and the edition does not create a different reading sequence. This is a limited physical edition, offered by the publisher while supplies last. Its design can matter to a collector without being necessary to follow Cassie's next case.
The four-book collection and the paperback box: what's included?
The core four are The Naturals, Killer Instinct, All In and Bad Blood. The collection below is an ebook bundle that also includes Twelve. It is not a physical box. Little, Brown's separate paperback boxed set also contains the four novels, with Twelve printed at the back of Bad Blood. Neither includes Dangerous Impulses.
Four novels plus a novella
The Naturals Four-Book Collection (ebook)
The original arc together, with Twelve as a bonus
The Naturals, Killer Instinct, All In and Bad Blood are collected together, with the novella Twelve included as extra reading. The four novels supply the original investigative arc and the relationships carried into the 2026 continuation.
The bundle gathers the same four novels sold individually. It is digital, so it does not supply a physical case, matching hardcovers or the Deluxe edition's decorative features. Dangerous Impulses is separate. Since Twelve is already included here, a second copy of the novella may duplicate content; it can still be left until after book five in your reading sequence.
What to read before Dangerous Impulses
The four original novels establish how the group works, why certain cases strike particular characters so hard, and the history behind its trust and tensions. Dangerous Impulses begins with the aftermath of that shared experience. Starting there would turn earlier developments into background information before seeing how they happened.
Twelve serves a different purpose. It looks ahead to an adult stage of Cassie's life rather than filling the eight-month interval before the new novel. The first four books are the preparation that matters for the fifth; the novella remains a separate decision about when to see that later period.
Is The Naturals connected to The Inheritance Games?
Jennifer Lynn Barnes wrote both series, but The Inheritance Games is a separate story, not a prerequisite for meeting Cassie. Its inheritance puzzle and The Naturals' FBI investigations share an interest in hidden motives and relationships, without forming one numbered reading sequence. No Hawthorne book needs to be inserted between these novels.
More November mysteries
Dangerous Impulses brings a returning YA team into November's releases. The monthly thriller and mystery selection covers other forthcoming novels, including adult suspense and espionage, while the thriller shelf gathers books already covered on BRG.
November 2026 thriller and mystery releases · Explore the thriller shelf
Quick answers
Questions about the order and editions
What order should I read The Naturals books in?
Start with The Naturals, Killer Instinct, All In and Bad Blood. Publication order puts Twelve next, then Dangerous Impulses. Reading book five before Twelve instead follows the characters' timeline.
Is Dangerous Impulses book five?
Yes. It is the fifth main novel, scheduled for November 3, 2026 in the US. Twelve is a separate novella.
Do I need to read Twelve before Dangerous Impulses?
No. Twelve is set later in Cassie's life. Leaving it until afterward keeps its future glimpses out of the main sequence.
Can Dangerous Impulses be read as a standalone?
It continues the established team's relationships and the emotional aftermath of Bad Blood. The first four novels provide that foundation.
What is different about the Deluxe Limited Edition?
It is a physical hardcover with decorated edges, special case design and endpapers, jacket effects and a ribbon. No bonus story chapters are announced.
Does the four-book box set include Dangerous Impulses?
No. The four novels run from The Naturals through Bad Blood. The ebook collection shown here also includes Twelve; Little, Brown's paperback box prints Twelve at the back of Bad Blood. Book five is separate.
Is The Naturals connected to The Inheritance Games?
They are separate series by Jennifer Lynn Barnes. You do not need to read The Inheritance Games before starting The Naturals.
How many main novels are there in The Naturals series?
Four are published as of October 22, 2026. Dangerous Impulses is the forthcoming fifth. Twelve is a novella, so it does not increase the main-novel count.
Sources
Sources for this guide
Series chronology, publication plans, edition features and collection contents checked October 22, 2026.
- Little, Brown: The Naturals series
- Little, Brown: The Naturals
- Little, Brown: Killer Instinct
- Little, Brown: All In
- Little, Brown: Bad Blood
- Little, Brown: Twelve
- Little, Brown: Dangerous Impulses Standard Edition
- Little, Brown: Dangerous Impulses Deluxe Limited Edition
- Little, Brown: the four-ebook collection and novella
- Little, Brown: paperback boxed set contents