Cipher: Lethal Algorhithm

US Marshals: Task Force 9 #2

by Ellie Masters

A legendary hacker on the run. A dominant US Marshal sent to capture her. One island safe house.

You've spent three years running from the monsters who burned your life to the ground — and now the only safe place left to hide is in the arms of the man sent to capture you.

Ivy is a ghost. The legendary hacker known as "the dragon," she survives on cold logic, burner laptops, and one steel-clad rule: never leave a footprint. She burns the Consortium's financial networks to make them pay for the friend they stole from her, and she never stays anywhere long enough to let the world touch her. Until a high-stakes zero-day in Macau goes wrong, and she's cornered in a dark parking garage.

Enter Julian Rhodes. US Marshal. Task Force 9 — the off-books federal unit that handles the targets who don't exist. He's spent eleven weeks tracking a shadow, and he isn't about to let her slip. Cocky, controlled, and hyper-confident, Julian lives to own the room. But when he finally captures his target, he doesn't find a cold corporate threat. He finds a sharp, defensive genius whose isolation trips every protective instinct he's spent his career locking down.

Forced into proximity in a remote island safe house, they run a joint extraction against a degrading seventy-two-hour window. His steady, load-bearing calm meets her razor-fast digital shields, and the friction sparks a heat neither can control. Under his roof, Julian gives her something she's never let herself have — the grounding safety she's been starved for since the day she ran.

Then a brutal ambush compromises their extraction, and Ivy makes the ultimate play to keep him alive: she cuts him out, secures the drive, and vanishes into the cold Shinjuku rain.

Julian doesn't take abandonment lightly. He survived the crossfire, and he's crossed an ocean to bring his ghost home — a digital trap built to catch her one-of-a-kind signature, waiting for the moment she slips. Because once you surrender to a protector, he never lets you run again.

214 pages, Kindle Edition

First published August 4, 2026

About the author

Angsty, Steamy, Heart-Stopping, Pulse-Pounding, Can't-Stop-Reading Romantic Suspense.

Ellie Masters is a USA Today Bestselling author and Amazon Top 15 Author.

In addition, she's a wife, military mom, doctor, and retired Colonel.

She writes romantic suspense filled with all your sexy, swoon-worthy alpha men. Her writing will tug at your heartstrings and leave your heart racing.

Born in the South, raised under the Hawaiian sun, Ellie has traveled the globe while in service to her country. The love of her life, her amazing husband, is her number one fan and biggest supporter. And yes! He's read every word she's written.

Don't forget to sign up for her newsletter. Never miss another release, sale, or exclusive. https://elliemasters.com/NewsletterSi...

Reviews

[LELANI DEKKER · Rating 5 out of 5]

Another fantastic book by Ellie Masters.Just like the Cerberus series,this series also tracks a Consortium with all the suspense,close proximity,an unwavering touch her and die alpha protector,a hacker with trust issues and scorching heat.Absolutely recommended with 5 stars.Now waiting (not so) patiently for Wraith...

[Roxs Reads · Rating 5 out of 5]

I'm loving the U.S. Marshals series. New threats to take down and new heroes to fall in love with. Legal Algorithm: Cipher is suspenseful and had me on edge to the very end.

Julian and Ivy are the perfect love match. Geniuses in their own right; their cyber knowledge blew me away, when it wasn't confusing the shit out if me, LOL! There is a lot of computer geek talk, but it all amazed me. Their love of the cyber world took center stage, and then they took that passion to the bedroom. Well, when they made that far!

Sweet and loving isn't how I'd describe this couple. They were all about getting to the endzone, whether in the trenches of the dark web, or in their need for physical release. They were both on the same page, and it made for some fantastic reading.

Not surprisingly, author Ellie Masters has delivered another 5-star story. I noticed a significant change to her writing with this book, for the better. I loved how improved her descriptive language was and the sentences were cleaner, leaving out those pesky filler words. I never tire of her writing and I look forward to book #3.

[Melanie · Rating 5 out of 5]

Wow! Where to start? Cipher is full of suspense and intrigue with some danger mixed in. And, yes there is a steamy romance sizzling under it all. But the emphasis here is on cyber warfare. Julian "Cipher" Rhodes, US Marshall is smart, savvy, determined and one of the best in his tech field. He may met his match in Ivy. He's been tracking her work for months before he finally finds her. She"s spent three years trying to right a wrong. She's equally adept at coding, getting in and out of networks without being caught and building traps. Together they take on something/someone bigger and more influential than they suspected. The attraction between them is palpable but she's not big on trust. He's wanted her fron the outset. He becomes her partner and protector. I cheered for them start to finish. Another stellar outing from Ellie Masters, not that I expected anything different. Thoroughly enjoyable!

[Tesh · Rating 5 out of 5]

These two, Julian and Ivy were such a great match. Their commonalities were in the same vein and I enjoyed that similarity right from the start.

Hacker Ivy was trying to bring down the Consortium, when US Marshall Julian Rhodes tracks her.

I really loved the way Julian could be smug, arrogant, but soft and forthright. Especially to Ivy. Yet she was super smart and switched on to what they wanted to do yet she been trying to do for the years single handedly.

I also deeply respect the expertise and research that went into the story. Totally above the mark so kudos for that Ellie.

The romance was deep, the plot exciting and the elements of suspense always there. So good, terrific actually!

[Elizabeth · Rating 5 out of 5]

I cannot imagine how soul destroying it must be to spend three years in virtual isolation, but that is what Ivy did in her quest to destroy the Consortium. I must confess that most of the technical computer language goes right over my head, but the essence of it is amazing. This is a story so full of tension, verging on desperation and heart stopping action, especially once Julian finds her. There are moments that brought tears to my eyes and dialogue that made me smile. A book that is really hard to put down even when falling asleep, but who needs sleep when there is a story to finish! Ivy will find a place in your heart and make you want to hold her tight and that is just what Julian does.

[Lynda · Rating 5 out of 5]

Arc review. CIPHER: Lethal Algorithm (US Marshals: Task Force 9 Book 2) is typical of Ellie Masters in many ways but unbelievably high tech. Julian and Ivy are unmatched at what they do, Ivy hacks and Julian protects but their common goal is to destroy the Consortium. Their chemistry builds slowly as they work together to find the high ranked person behind it all. When the case erupts their relationship does too. Ivy will give up Julian to make sure he is safe while Julian searches for as he can’t live without her. This is an action packed page turner with two people who work to not only keep their world safe but to find their HEA.

[Alison Ramsay · Rating 5 out of 5]

A fast action thrill read as Ivy and Julian try to outsmart and out-code the Consortium. Danger has followed Ivy for the last three years as she has tried to dismantle the Consortium finances using her unique hacking skills. Enter US Marshall Julian who has been searching for her for weeks. Together they are a lethal force against the bad guys. Romance blossoms in adversity and this is an enjoyable romantic adventure.

[Liz Sadowsky · Rating 5 out of 5]

Hang on to your hat for this one! Julian and Ivy’s story is non stop, page turning action from the first page till the very end. These two find an unbreakable bound on how they see and think their way through anything digital. It’s a wonderful read and the characters of US Marshals: Task Force 9 knows how to deliver!

[Carolyn Spence · Rating 5 out of 5]

Nothing like computer jargon to sound sexy from Julian. Ivy is his match in every way and doesn't hold back, she's just not used to having a partner. These men are no nonsense for sure, "Start the coffee." and some sense of humor when required, "budget cuts". This book is full of power moves by each main character. Mesmerizing.

[Susan · Rating 5 out of 5]

I'm so enjoying this new US Marshal series! Julian and Ivy's story was a match made in heaven as they are both computer geeks. I loved how Ivy singlehandedly was able to dismantle an entire corrupt network of bribes and murder for hire plots. A fast past read with two very likeable characters, action, suspense and steam! I'm already looking forward to the next book.

[Sherry Wood · Rating 5 out of 5]

Intense!

Amazing, exciting, intense and fast paced throughout the whole book!! Suspense, tense moments, action, this book has it all!! And a beautiful love story that trust is hard to give but is required. I totally loved this book and definitely recommend reading!! Another awesome masterpiece from Ellie Masters!!!! 5++++ stars!!

[Janice Stansell · Rating 5 out of 5]

Wow! This one hits the ground running and is non-stop all the way through! The intensity, the tension between Ivy and Julian is off the charts. This will break your heart, steal it and mend it. NEVER disappointed when I read one of Ellie’s stories!

[Anny · Rating 5 out of 5]

Very lethal and absolutely loved it!!!

​A perfect 5-star read! Julian's and Ivy's love story is a lethal worth taking. Ellie Masters ’ storytelling is top-notch as always. I can't wait for the next book in the series!

[Lori Hammons · Rating 5 out of 5]

Julian finally tracks down his ghost, Ivy. She's brilliant at what she does, the way she thinks. Julian is her match. This is an amazing romantic high-tech suspense.

[Tom Prejsner · Rating 5 out of 5]

Romance

Thank you for sharing these wonderful romance novel series books. Please keep writing more of these wonderful stories. Thank you

[Diane Werning · Rating 5 out of 5]

Cipher

What an intense read.The characters were amazing and the story was really good.While you read this it will feel like you are there watching it happen.Happy reading.

[Alison Nyland · Rating 4 out of 5]

I enjoyed this book. However it is very technical with computer terms and had a tough time following some of the book. Good book though even though I had to gloss over some of it.