
Every crime tells a story…
But not every killer is the villain.

The Serpent’s Order
The Serpent Series Book 4
by S.Z. Estavillo
Genre: Thriller, Romantic Suspense

An assassin bound by obedience. A detective marked for death. A cartel war with no survivors.
Von Schlange thought she’d escaped her past. Now Black Nova owns her—an elite, off-the-books task force where obedience is survival and failure means death. As their newest assassin, she’s unleashed on targets tied to Jaxon Ryker, a drug lord buried deep in the Alaskan wilds.
Her partner, Xander Holt, a former Navy SEAL with ice in his veins, lives by the same brutal code: no attachments, no lines crossed. But as missions turn bloody, the fragile boundary between partner and lover begins to blur—and desire becomes its own kind of danger.
Across the country, Detective Anaya Nazario faces a nightmare of her own. A synthetic “zombie drug,” deadlier than fentanyl and immune to Narcan, is ripping through Los Angeles. Her investigation exposes a network of dirty cops shielding Ryker’s empire—and puts a target squarely on her back.
Two women on opposite fronts. One war against corruption and cartel power. And a single truth—every betrayal leaves a body behind.
Explosive, unrelenting, and razor-sharp, The Serpent’s Order propels the Serpent Series into its most dangerous chapter yet—where justice is a myth, and survival comes at a price paid in blood.
**NEW RELEASE on Feb 10, 2026! PreOrder Now!**




Twilight of the Serpent
The Serpent Series Book 3

Some predators hide in plain sight. Others hunt from the shadows.
Merrick Winslow is a decorated Army officer, a man of discipline and honor—or so he claims. When he reports that his ex-wife, Cheonsa Soo-Min, has been stalking him, no one questions his story. He paints her as unstable, vengeful, and dangerous, a woman consumed by obsession. But when two officers are gunned down with her own weapon, the truth becomes harder to see. With the law closing in, Cheonsa vanishes, fleeing to Rio de Janeiro, where she is taken in by Von Schlange, the vigilante thought to have disappeared for good.
Von has retired her vengeful ways, leaving behind a life of bloodshed to run a quiet veterinary clinic. But when Cheonsa’s past collides with Winslow’s lies, the two women begin to unravel a deadly deception—one that turns predator into prey. By the time Von uncovers the truth, an innocent life has already been taken.
Now, there’s only one thing left to do: find the real monster and make him pay.
Meanwhile, in Los Angeles, Detective Anaya Nazario and Supervising Special Agent Blake Huxley are adjusting to life as new parents. But after only four months of maternity leave, Nazario is pulled back into the field to investigate the murder of two officers. What should be a straightforward case quickly spirals into something far more sinister—secrets buried beneath the badge, a killer hiding behind a uniform, and a web of corruption stretching further than anyone expected.
As Nazario and Huxley chase down leads, their investigation intersects with a vigilante they once thought was dead. And this time, Von Schlange isn’t just seeking justice—she’s delivering retribution.
For fans of Karin Slaughter, Gillian Flynn, and Taylor Adams, Twilight of the Serpent delivers a high-stakes vigilante thriller packed with morally gray justice, relentless suspense, and a tangled web of deception. Perfect for readers who love strong female leads, intense cat-and-mouse chases, and dark psychological twists.



The Serpent Woman
The Serpent Series Book 2

The exciting sequel to The Serpent’s Bridge…
A serial killer is on the loose. With her insidious tattoo and venomous killer strike, they’re calling her the serpent woman.
Two of the best in their field, LAPD Detective Anaya Nazario and FBI Supervising Special Agent Blake Huxley are forced to work together yet again, despite their strained romantic history and a baby on the way. Together on a nationwide hunt, they must find this serpent woman before she strikes again.
But, as the cat-and-mouse chase evolves, Nazario and Huxley begin to realize that their killer is on a mission of vigilante justice and they must struggle with the question of who really deserves their justice: The killer, or her victims?
This dark thriller delves into the sensitive topics of sex trafficking, child abuse, animal death, sexual assault, graphic violence, and dead bodies. Reader discretion is advised.



The Serpent’s Bridge
The Serpent Series Book 1

Compelling dialogue, rich, gritty prose, and characters you won’t forget — if you loved The Girl Who Kicked the Hornets Nest by Stieg Larsson, or Ink and Bone by Lisa Unger, you’ll love The Serpent’s Bridge.
Recovering alcoholic Detective Anaya Nazario remains haunted by her father’s murder. Lucas Nazario was the highest-ranking Puerto Rican LAPD detective, and his case has gone unsolved for twenty-four years since his murder. When Mexican immigrants are targeted by a serial killer, Nazario senses a connection and fights to keep the leadless case open. The homicide investigation centers on Sanctuary Baptist, a church composed of immigrants led by Pastor Stan and his wife. Nazario’s personal and professional worlds collide when she is compelled to collaborate with her former lover, Special Agent Blake Huxley. As their lives merge once more, the FBI and Detective Nazario stop at nothing to find a killer.
Is this the same monster who killed her father and left him for dead under a bridge?
Can she put a stop to the murders before more families lose loved ones?





As a BIPOC thriller author, she previously parted amicably with her agent and, three months later, secured an eight-book deal with Oliver-Heber Books—now boasting 24,000 downloads in its first year and a BookRaid bestseller ranking in the thriller category. The Serpent Woman (Book 2) reached #1 on Amazon and topped all three of its categories. Her background spans literary agencies and TV studios, where she contributed to greenlit screenplays that became Lifetime movies. She holds a Master’s in Television, Radio, and Film, has taught author branding workshops (L.A. Writer’s Conference, North Texas RWA), and maintains a 100K+ social media following.
Website * Facebook * X * Instagram * Bluesky * TikTok * Bookbub * Amazon * Goodreads
My Thoughts
Book One
The Serpent’s Bridge
This is a new to me author, so I was absolutely thrilled to be able to review the whole series. This is a very gritty character driven thriller that is set in Los Angeles. We get to meet Detective Anaya Nazario. She is a recovering alcoholic and is haunted by her past and her father‘s unsolved murder. Her father also was the highest ranking Puerto Rican LAPD detective and his death was under mysterious circumstances.
A serial killer starts to target undocumented immigrants, leaving their bodies and sacrilegious ways. Anaya is drawn to the case and is seeing parallels to her own father‘s death. She is assigned to the investigation and she gets to work with FBI special agent Blake Huxley. There is definitely tension since this is her former lover.
I think one of my favorite thing about this story besides, the action in the suspense is that the characters are complex. This is also told as a multiple point of view. The author has woven everything together seamlessly.
Book Two
In book 2, the action picks up right where it left off. A serial killer has now been dubbed, the serpent woman. The serial killer is accused of murdering predators who have escaped justice.
We’re back with detective Anya, Nazario, and FBI agent Blake Huxley. They start to dig deeper into the case and they realize that this killer is not acting at random. I love the cat and mouse pursuit along with the multi layers that the author is well known for.
I am super excited to tell you about book 3 next
Book 3 is entitled twilight of the serpent. This might have been my favorite book within the series. There was a lot going on, but it was easy to follow.
There are two police officers that are found murdered. Anya and FBI special agent Blake are on the case to investigate the killing of the two officers. The two dig in and they are quickly finding corruption and shadows behind the badge. This book is definitely a very tense and dark thriller, and I enjoyed every minute of it.
And that is gonna bring us to book 4 in the series the serpent order. I want to say Bravo to the author. This series kept me on the edge of my seat, and I devoured it all within a weekend. I really hope to read more from her in the future, and I am so excited that I was able to be part of this tour.
That being said book 4, we are seeing a war against corruption and cartel power. Some of my most favorite types of thrillers.
This book is also told by multiple points of views and one of the things I love about this author is the fact that she weaves them together so seamlessly that you don’t feel like you’re lost. I absolutely love, strong female characters.
Thank you so much to the author, publisher and silver dagger book tours for allow allowing me to take part in this tour. All thoughts on my own.
GIVEAWAY
Follow the tour HERE for special content and a giveaway!