Deep Undercover

True Blue K-9 Unit #4

by Lenora Worth

A dangerous undercover assignment…

To take down a serial bomber, NYPD K-9 officers Brianne Hayes and Gavin Sutherland must go undercover—as a married couple. But now the bomber is targeting them to halt the investigation. As the clock ticks down, can Brianne, Gavin and their K-9 partners find the culprit in time to save the city—and their own lives?

Genres: Romance, Christian Fiction, Suspense, Romantic Suspense, Love Inspired Suspense, Harlequin, New York

288 pages, Mass Market Paperback

First published July 1, 2019

About the author

Lenora Worth has written 75 books for three different publishers. She reached a milestone when she received her 50th book pin from Harlequin. Her books have won both regional and national awards and she now has millions of books in print and is a NY Times, USA Today and Publishers Weekly bestselling author. Currently she is writing both Love Inspired and Love Inspired Suspense and Tule Publishing. Married to her childhood sweetheart, Lenora has two grown children and lives in Florida.

Pen name: Lenora Nazworth

Reviews

[Paula · Rating 5 out of 5]

A serial bomber is on the loose in New York City and K-9 officers Gavin and Brianne are on the case along with their trusted bomb-detecting canine partners Tommy and Stella. I really liked that the hero and heroine were both K-9 officers in this story. Gavin and Brianne made a terrific team, and they were great together both personally and professionally. I especially enjoyed when they went undercover. The K-9 dogs, Tommy and Stella, were pretty awesome and wonderful at their jobs. The ongoing storyline in this series still remains unsolved, but the serial bomber storyline wraps up by the end. A thoroughly entertaining read with very likable characters, both human and canine.

[Tina Loves To Read · Rating 4 out of 5]

This is a Christian Romantic Suspense, and this is the fourth book in the True Blue K-9 Unit series. I read the first three books in this series before picking up this book. I read this book by listening to the audiobook for this book, and I really enjoyed the audiobook. I really enjoyed this series and this book. This book is filled with suspense and romance throughout this book. I really loved the characters, and I could feel the connection the two characters had. I received an ARC of this book. This review is my own honest opinion about the book like all my reviews are.

[Kav · Rating 5 out of 5]

Whew! What a gripping opening scene! Vivid descriptions of a panicking crowd left me hyperventilating! Not one, but two, K-9 officers (and their humans!) to the rescue.

I'm loving this True Blue K-9 Unit continuity series. Deep Undercover is the fourth book but can be read as a standalone. However, I'm really bonding with this team of K-9 Officers and their elite dogs so it's always a thrill to meet up with the gang in each book.

This time it's Tommy and Stella's turn to sniff out clues and bring criminals to justice...well, they do get a little help from Gavin and Brianne. :-) If only the humans got along as well as their dogs though!

Gavin's got a bit of a chip on his shoulder. Ambition and pride have caused him some trouble in the past. He's trying to live that down but Brianne doesn't always make it easy for him since she's a tad guarded and a whole lot prickly. She also has a tendency to react defensively as she sets out to prove that female officers are just as capable as their male counterparts. Gavin totally gets that, but it doesn't stop him from going into protective mode now and again which drives Brianne crazy because -- hello, she's a cop too! Love the dynamics between this hero and heroine. Almost as gnarly as the suspense!

Another page-turning addition to this stunning series!

[Patrizia · Rating 4 out of 5]

Questo libro mi è piaciuto un filino meno dei precedenti, ma raggiunge comunque una buona valutazione.

[Carla · Rating 4 out of 5]

A serial bomber is terrorizing NYC, and NYPD K-9 officers Brianne Hayes and Gavin Sutherland accept a dangerous assignment. They are tasked to pose as a married couple, to find those behind the attacks. With real estate at a high, and tenants refusing to leave their rentals, how can they get them out, destroy the building. When the bomber realizes that they are hot on their trail, they become the targets. With the help of their highly trained K-9 partners, The stakes escalate dramatically when the bomber realizes they are closing in and turns his sights directly on them to end the investigation. Working alongside their highly trained K-9 partners, Brianne and Gavin must race against the clock to unmask the culprit before they lose their lives. Sasha and Gus are both bomb sniffing, patrol and apprehension K-9s and work well with their handlers. Can they find the bomber, and those behind the targeting of the various buildings before another bomb goes off?

This is another fast paced, action story. Gavin and Brianne work well together, despite their initial hesitation. They know that they have find whoever is behind the series of bombings as well as the bomber. The treat of another bombing adds tension to the story, but it's nice that there aren't a lot of murders to solve. I enjoyed seeing Brianne and Gavin pose as a wealthy couple, with it being over the top at times, making me snicker a bit. I found the plot of bombing buildings to drive out tenants so they can sell the property to build expensive new condos to be a bit too realistic. With urban development all over the world driving up prices, it is a bit scary to think that this could really happen. Of course, I loved how Sasha and Gus were integral to the solving of the crimes, using their skills for tracking and takedown. I enjoyed this story, the plot, the characters and especially the K-9 partners. If you enjoy K-9 stories, with a bit of faith and romance thrown in, then I recommend you pick up Deep Undercover. Callie Beaulieu narrates this book and does a wonderful job with the characters, their accents and personalities. I enjoyed listening to the story.

[Elaine · Rating 3 out of 5]

So this was a sweet story but I feel like it dragged a bit in the middle.
I also feel like the two main characters needed to figure things out. I felt like they just kept going in circles for no reason.

But, aside from that, it was sweet. It involves dogs in a K-9 unit. And it involves bombs.
Not a very likely combination, but here we are. And… the dogs are trained to sniff out explosives!

Crazy scenarios galore, but it definitely brought some sparks to the scene. And kept me guessing!

Oh… and I loved Brianne’s Mom. Oh, you’re dropping her off? Stay! I’ll make meatballs for dinner. No… it’s no trouble! 🤣

So, if you love dogs and are up for some scary explosive scenes… definitely pick this one up!

#DeepUndercover by @LenoraWorth and narrated beautifully by @CallieBeaulieu.

3 1/2 stars for me! ⭐️⭐️⭐️💫

This one has not been released yet. Please look 👀 for it today, July 7, 2026!

Thanks so much to #NetGalley and @HarlequinAudio for an ALC of the audiobook in exchange for an honest review.

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And as always, thanks for reading along with me! 📚⭐️📖🩷

[Beth Reynolds Winters · Rating 5 out of 5]

I love these k9 books. All of the authors have been very good. I love reading series such as this True Blue K9 Unit.

[maddy · Rating 3 out of 5]

three stars for the dogs

[Glenda Parker · Rating 5 out of 5]

My review today is one the Love Inspired Suspense, Deep Cover. This is book four in the True Blue K-9 Unit Continuity Series. I have really enjoyed this series. It has been written by some of my favorite authors. This book is no exception. I am a true fan of Lenora's work. This book is well written, action packed, and full of faith. I know you are going to love it. Although it is part of a series but it is a book that can stand alone. A great read!

K-9 Officer Gavin Sutherland has had some problems in his unit. He had made no bones about the fact that he felt he deserved to have the chief's job but Jordan Jameson got the job. He was really upset about the whole thing but then Jordan was killed and all eyes looked to him. Then his brother Noah was given the job. Gavin can't help being a little bit bitter. He is determined to find Jordan's killer. Now he and his partner Tommy are assigned to watch the shoulder of the East River waiting for the fourth of July fireworks. Tommy is a bomb detection dog. His rookie partner, a woman that he finds extremely attractive, and her K-9 partner walks up to him. Bringing him a bottle of water. Both dogs alert and Gavin sens the rookie and her K-9 after the man who had recently had a backpack but didn't now. Tommy alerts and he finds the backpack and Gavin tries to get people clear of the area. The crowd panics. The bomb goes off but everyone is safe for now.

Rookie K-9 Officer Brianne Hayes was to have graduated the day their boss disappeared and was later found dead. So now she is the rookie without certification. Stella, her K-9 partner is being trained to bomb detection. Brianne felt like she had to work harder than the others to prove her worth. She has some real trust issues. She hadn't been happy to be pared off with this man but now her thinking has completely changed and she finds herself attracted to the man.

They find themselves in a journey to find the bomber. They go undercover as a married couple to try to flush out the killers. Fighting their attraction they must learn to trust each other but find themselves in deep trouble. God has a plan for these two, a plan for a hope and a future. God has a plan for you too. Give Him your heart and watch Him turn our life around.

[Meagan Myhren-Bennett · Rating 4 out of 5]

As the New York K-9 Unit continues to work on the murder of their boss and the disappearance of his K-9 partner Snapper, they have a serial bomber to deal with too. NYPD K-9 officers Brianne Hayes and Gavin Sutherland have suspicions about a realty group and decide that the only way to get the truth is to go undercover.

There is just one catch to Gavin's plan - they'll have to go undercover as a married couple. A couple with money to spend and a spoiled dog who goes everywhere with them. Yes, Gavin's K-9 partner Tommy is going undercover as a spoiled pooch in the hopes that he can sniff out evidence leading them to the bomber.

But when someone starts targeting the pair, the only question is whether it is related to their bomber or to Jordan's murder.

This is the fourth book in the True Blue K-9 series and it continues the story arc that has been running throughout the series - what happened to Jordan Jameson and why. Will the K-9 unit ever get to the truth? If you have not read the previous books that should not be a problem - as this story while having the series thread running through it focuses more on Gavin and Brianne's bomb detection work and their undercover operation. And as this is a Love Inspired Suspense there is of course a possible romance in their future - all clean reading too.

[Robin Loves Reading · Rating 4 out of 5]

A serial bomber is on the loose, placing countless lives at risk. K-9 officers Brianne Hayes and Gavin Sutherland go undercover, hoping to flush out the bomber before another attack can occur.

Danger is never far away as Brianne and Gavin race against time. At the same time, another complication begins to surface. Both Brianne and Gavin realize that there is a growing attraction between them. Balancing their dangerous assignment with their developing feelings adds an emotional layer to this fast-paced romantic suspense.

Deep Undercover is the fourth book in Lenora Worth’s True Blue K-9 series. Originally released in 2019, this is a series I didn’t have the opportunity to read when it first came out. It has been a pleasure catching up on these books, and each one has only increased my appreciation for the series. With its blend of suspense, action, engaging characters, and loyal K-9 partners, I’m very much looking forward to reading the rest of the series. Something else that I have been enjoying with these rereleases is the wonderful narration for each of the books. The narrators capture the characters with flair.

Many thanks to HarperCollins and to NetGalley for this ARC for review. This is my honest opinion.

[Lghiggins · Rating 4 out of 5]

Clean romance? ✔️ Harlequin Love Inspired Suspense

Christian themes? ✔️ but not preachy

K-9 officers? ✔️ 2 bomb detection dogs, highly trained

Likable protagonists? ✔️ 2 human officers who have to work at not falling in love

Interesting setting? ✔️ NYC, the upper crust and the underbelly

Realistic backdrop for crimes? ✔️ includes difficulties with traffic, use of various forms of urban transportation, gentrification of older neighborhoods, high real estate prices

Complex plot? ✔️ Brianne and Gavin and their K-9 partners are initially assigned to investigate the death of the leader of their unit, but soon their attentions are soon directed to a serial bomber.

Undercover? ✔️ Brianne and Gavin have to pretend to be married and have “money to burn” in their search for a building to renovate or demolish

Suspense? ✔️ Absolutely, but not the kind that will keep you up all night

Standalone? ✔️ Each book in the series is written by different author

Narration? ✔️ Very good

Recommend? ✔️ Absolutely!

I received a complimentary copy of this book in exchange for an honest review. Opinions expressed in this review are completely my own.

[Yvonne Cruz · Rating 4 out of 5]

We are back with New York’s finest K-9 Division. A place where the team is still mourning the murder of their leader. One that remains unsolved. But the work must continue and this time the story belongs to K-9 officers Brianne Hayes and Gavin Sutherland.
A bomber seems determined to create havoc in the city so these two decide that going undercover as a wealthy couple, might be the key to solving the crime.
As they navigate the investigation, and real estate properties that might have clues to it all, the danger and feelings between them intensifies. But first, the bomber has to be found and brought to justice.
Will they accomplish their goal and still stay alive? If they do, will they realize that they could truly have a future together?
This was a very engaging addition to the series. The narrator, Callie Beaulieu manages to bring the story to life for greater enjoyment of the plot.
I was entrusted a copy of this audiobook by Netgalley and Harlequin Audio.
The opinions expressed are solely my own.

[Susan · Rating 5 out of 5]

This is another great installment in the True Blue K-9 series with plenty of action throughout. This book can stand alone even though it is part of the series. There is plenty of information on the background of what you need to know from the other books.

I enjoyed reading about the two K-9s and their handlers that need to work together to solve the case. I would have loved to see the story revolve around the dogs a little bit more but overall I was really happy to see them in action and especially when they were alerting to bombs because that is a different skill than you typically see in the K-9 books. That definitely made this stand out for me from other books with K-9s.

The main characters have good chemistry and this book is very well written. The author definitely knows how to keep a reader's attention and the audiobook did a great job at bringing her work to life. I enjoyed how the characters in this one went undercover as a married couple to try to find the suspects. A great suspense book and a unique dog skill brought to the forefront that we don't usually get to see.

[Debbie · Rating 4 out of 5]

"Deep Undercover" is a Christian romantic suspense. It's the fourth book in a series but works as a stand alone novel. The main characters were likable and reacted realistically to events. Brianne and Gavin were both police officers with K9 bomb-sniffing partners. They worked together to figure out who's bombing old buildings on prime land so it can be bought for cheap and renovated or rebuilt.

They respected each other and generally worked well as a team. They weren't really undercover: in their free time, they occasionally dressed up like a rich couple and posed as clients looking for an old building to buy cheap to renovate. Gavin liked that Brianne trusted him and was willing to work with him on this project since others on the K9 team had suspected him of wrong-doing (in the first book). The suspense came from the physical danger to Brianne and Gavin as someone kept trying to kill them. There was no sex or bad language. Overall, I'd recommend this exciting novel.

[Cheryl · Rating 4 out of 5]

I was grateful to receive an audio of Deep Undercover. Thank you, Harper Audio, Harlequin, Love Inspired Suspense. I enjoyed the narrator. Gavin is a seasoned K-9 officer, Breeann is a new recruit who graduated at the top of her class. Someone is setting off bombs in older buildings which are then sold and turned into new top-notch buildings. We go along with Gavin and Breeann (and their K-9's) on the hunt for the bomber while they are dealing with their feelings. Deep Undercover has a plot line that runs through each book, but each book stands by itself, each book has a plot and a couple. Thank you for the advance copy of the audio. I freely share my honest thoughts and opinions. #DeepUndercover TrueblueK-9 #LeonoraWorth #HarperAudio #Harlequin #LoveInspiried Suspense NetGalley

[Faith · Rating 5 out of 5]

NYPD K-9 officers Brianne Hayes and Gavin Sutherland go deep undercover as a wealthy married couple to stop a bomber they call The Tick before it's too late.

Brianne and Gavin are thrown together in this fast-paced adventure, as they get to know each other, they bond over their shared convictions and love of working with their K-9 partners. I liked their interaction, and connection. There was a lot going on, as well as continuing to keep up with the background story arc that connects the series.

Overall, a highly enjoyable read with great characters, mystery, tension, faith and great dogs.

I received a complimentary copy of this book. Opinions expressed in this review are completely my own.

[Hazel Robinson · Rating 3 out of 5]

Slow, oh so slow

Not sure what happened with this part of the True Blue series. This book was very slow. It took me almost a week to finish it. Several times I all most stopped. I have read other books by this author but this one missed the mark. Happy that Gavin had proved himself to the other K9 officers after his blow up about Noah getting the captain's job after someone killed Jordan. Bree was awesome glad that she helped Gavin get over the feeling of abandonment from his mother. Bree also realized that Gavin was not like her ex-boyfriend and she could trust him. This story has bombs, attempted murder, and a few other surprises.

[Heather Herring · Rating 4 out of 5]

Rating: 4.5
This was the first book I read in the serries and I loved the crime part of the book! The romance aspect isn't the best compared to other books I've read but by page 150, I was hooked. Lenora seems like a very devoted and kind author who loves what she does and you can tell just by reading her stories. I fell in love with her writing style the moment I started. Your sure to love this book! I really reccomend it! You can read the whole serries, or even as a standalone. I do suggest reading the whole serries in order though since it would probably be confusing out of order. I know I'm gonna check out the rest of the serries!

[Mary Baker · Rating 4 out of 5]

The first thing I noticed about this book was the author's use of verb tenses. It was nice to read without wanting to take out a red pen to make corrections on the pages. This was another book in the True Blue K-9 Unit series which I enjoyed. Finally, Gavin had a chance to prove that he wasn't as bad a person as others in his unit seemed to think he was. Of course, I thought his grumbling in front of others about not getting the job he wanted was immature and unnecessary. Nevertheless, by working with Brianne, he was able to redeem himself and improve his reputation. The dogs make the series what it is. Their skills are amazing.

[Toth Jo-Ann · Rating 4 out of 5]

This is well done. Its part of a series called True Blue. I like how Brianne and Gavin at first have conflicts but work thru it as the story evolves. Its got great action and I like how each story has its own mystery but the murder of their chief is still there to be solved. Lenora does a excellent job of combining the mystery of the bomber with the action of what is going on. Its well done and the series seems to flow well despite deferent authors for each book. I look forward to reading Terri Reed's book next. J

[Patricia · Rating 5 out of 5]

this is another great story in the k9 blue series. Bree and Gavin are both in the k9 unit but gavin is trying to find the boss's killer and who is setting bombs off all over town. i asked Bree to help him and they get the ok but no body knew what they would have to ga through to get the bomber, if you like suspense, romance and animals you willwant ot read the story. looking forward to the next story

[Jennifer · Rating 4 out of 5]

Deep Undercover is the fourth book in the series and a pretty good amount of action and bravery! With two K-9s and their handlers Gavin Sutherland and Brianne Hayes they go undercover to try and figure who is setting bombs and why? Many attempts are taken against them and as Gavin and Brianne work hard to solve the puzzle they also grow closer. Will they survive to have a chance at a future together?

[Janet Graham · Rating 5 out of 5]

Real Estate Bomber VS NYC K-9s
This book is the fifth in a series about NYC k-9s and their handlers. Each book in this series has its own plot but has an over-reaching story arc. They should be read in order to enjoy them the best. This story is about a bomber in NYC who seems to be targeting real estate. It is a very good plot and well planned. The story also has a nice, clean romance developing. The entire tale is faith-filled. I highly recommend this series.

[Linda Wilson · Rating 3 out of 5]

Brianne is a rookie K-9 officer assigned to work with seasoned K-9 officer Gavin. While as a July 4th celebration they detect a bomb. The book was good with a good story line. I would have enjoyed it more except for the narrator. It seemed she portrayed Brianne as whinny and a little short tempered. In spots the narrator seemed rushed.

I received this audio book by Love Inspired Suspense via Net/Galley for an honest review. I was not compensated in any way.

[Rebecca Trump · Rating 4 out of 5]

This story had me hooked. The forced proximity trope was intriguing and I enjoyed the flirting. Yet, the danger was so palpable and left me in a gasp at different moments. Not to mention the canine officers that were so adorable. If you enjoy mystery suspense novels, you will enjoy this series.

I receive a complimentary copy of this audiobook from the publisher. The opinions expressed are completely my own.

[Elaine Applebury · Rating 5 out of 5]

Deep Undercover is the 4th in the True Blue K-9 Unit continuity series. I love all the authors in this series and each book has been action packed. Gavin and Bree and their bomb sniffing dogs, Tommy and Stella, are the main characters in Ms. Worth's story of stopping a serial bomber. One can read this book as a stand alone title, but do yourself a favor and read the entire series!

[Cathy Beckett · Rating 3 out of 5]

I actually gave this book a 3.5 rating. I loved Gavin and Brianne. They were really fun. Bree has been targeted by a serial bomber. She has at least three attempts on her life but Gavin saved her each time. They go under cover to find the bomber and to stop a crooked real estate agent.
Their story was fast paced and well thought out. The author let the story unfold naturally.

[Shayne Archer · Rating 5 out of 5]

Deep Undercover

Deep Undercover by Lenora Worth pulls you into the story of Brianne and Gavin, along with their K-9's Stella and Tommy as they search for bombs. Together, they solve the mystery of the Tick, while God helps them deal with their past and promises love for their future together.

[Nicole · Rating 5 out of 5]

Deep Undercover by Lenora Worth, narrated by Callie Beaulieu. This is the 4th book in the True Blue K-9 series. Great characters, could be read as a standalone. Author did good informing you so you were not lost. Action packed, full of suspense with a touch of romance. Thank you to #NetGalley and #HarlequinAudio for this arc. This is my honest review. Releases July 7, 2026