Excellent series from one of my favorite.authors. Sloane McPberaon , a member of and underwater investigation unit is a fantastic character and her fierce attitude and take no prisoners approach to the cases make for a fun series. Sloane reams up with a grizzled old reporter named Gwen to solve a local murder after a body washes up on the beach. I finished the book in one day and can't wait for the next one!

Andrew Mayne writes not just great books with stellar gripping storylines but also has an innate ability to create new characters no matter how weird or questionable and make them likeable. If like me, you've read any of the books from the the Underwater Investigative Unit series you have more likely than not come to LOVE Sloan, Solar & Hughes. I've loved following Sloan's unusual & distinctive cases underwater, from the get-go and this was the first one of her cases mostly conducted on land. Not complaining! It was just as twisted & compelling as the usual Andrew Mayne book. While I really missed Big Bill or his mention in this book, it was a whole new 'whoa' for me! While this book has its usual dose of Sloanology, the Gwentuition is what hit it out of the park. Gwen is another quirky character I wasn't sure I liked in the beginning but have come to love her since. In Sea Castle, Sloan & Gwen, polar opposites of each other team up to catch a killer who's clever & is always 5 steps ahead of law enforcement.
I am a BIG FAN of this unusual little series & can't wait to read the next book Dark Dive!
Thank you NetGalley, Thomas and Mercer, Andrew Mayne for this arc!

Thanks to Netgalley and the publisher for this seaworthy epic mystery (eARC).

Andrew Mayne's latest thriller, Sea Castle, plunges readers into the murky depths of suspense, where secrets lie buried like ancient shipwrecks beneath the waves. As a reviewer, I can confidently say that this "turbulent whirlpool of intrigue and adrenaline" of a read will leave you gasping for air..

When a mysterious young woman washes ashore on a Fort Lauderdale beach, Sloan McPherson of the Underwater Investigation Unit is summoned to unravel the enigma. Her instincts scream murder, but the ocean conceals more questions than answers. To crack the case, Sloan seeks an unlikely ally: Gwen Wylder, the notorious Miami homicide detective. Gwen is as sharp as a harpoon and as unpredictable as a rogue wave. She demands Sloan's insights into unrelated cold cases and disappearances, hinting at a serial killer stalking Florida's coastline.

Sloan and Gwen's partnership is a tempest of wit and tension. Their banter crackles like lightning, and their contrasting personalities create a captivating dynamic. Mayne crafts realistically flawed, authentic characters. Sloan's vulnerability and Gwen's sharp edges make them equally relatable and memorable.

Mayne's vivid descriptions plunge us into the abyss, where coral reefs and shipwrecks harbor secrets. The ocean becomes a character in itself, its depths echoing with danger.

As the investigation unfolds, the plot takes unexpected twists. Just when you think you've caught the current, it sweeps you into uncharted territory. The narrative surges forward like a riptide, pulling you deeper into the mystery.

Sea Castle is a siren's call to thriller enthusiasts. Dive in, but beware—the undertow is strong, and the truth lies in the darkest trenches. Andrew Mayne has crafted a novel that's as gripping as a barnacle-clad anchor.

Dear readers, this book earns an enthusiastic Five-star rating (no life jacket required).

I have never read any of the other books by this author but felt confident in my ability to jump in and read this one without prior character knowledge. While I felt the storyline was compelling, there were parts that were not quite believable in how quickly they found a resolution (spoiler alert: how did Gwen know that she was in a cult that quickly? There was also only one sentence on how they found the kidnappers apartment 3 days later).

I will premise this review by saying that I love Sloane McPherson as a character and I have loved all of the UIU books to this point, but this one didn't work as well for me. There were several reasons for that: the UIU is largely absent in this novel, related to the events in Sea Storm; there was very little underwater investigating - Sloane is mostly on dry land for the bulk of the novel and she is in her element in the water; the plot seemed to drag on in spots before ultimately being quickly resolved.

I will certainly enjoy and look forward to future entries in the series, but I hope there's a return to the characters and elements that made the first 3 UIU novels so interesting.

I don't think this book would work especially well as a standalone read due to the references to prior events and the impact on Sloane, the storyline, and her relationships with coworkers.

This was my first book by this author and in this series. I’m definitely thinking I’ll go back and listen to the previous books because I love a good thriller series.

I received this an ARC but wasn’t able to read it right away, and then ended up getting an audio copy. The narration was good and it made for an easy listen. I didn’t have any trouble picking up with this current book though I’m sure having the back story on Sloan from previous books would have been helpful.

The storyline drew me in and kept me interested and the twists at the end came one after another, one I thought I saw coming but then it wasn’t what I thought it was and that one surprised me. I like when a book can surprise me.

I have to say I am a huge fan of this series, I love sloans character and her interactions with her team and her family.
Despise enjoying this instalment, i have to say I was left wanting.
I really needed more underwater action and more family and team interaction.
I hope we get more in this series, but really hope imwe can be taken back to the thrill of the first few books, the risks, the danger and the diving.

A fantastic read! I love Mayne's work and the world he creates for Sloan. It was fun to see her interact with some new characters and will be excited to see where the UIU goes from here.

Another solid read from Andrew Mayne and his awesome UIU (ish) series. I’ll be honest - I wanted this book to continue along the lines of the previous in the series, and am slightly disappointed there wasn’t as much underwater-based adventure, as I think that aspect makes this series such a standout. I was glad to see some Solar and Scott presence, but there wasn’t nearly enough. I liked the story well enough, and found Sloan working with Wylder to be interesting, especially as it advanced Sloan’s character so much (much more thoughtful and responsible!). The mystery was intriguing, the detecting solid, and the pacing good. I felt the ending was very rushed and would have liked more resolution there. Thrilled by the very end and the band being back together in the next book!

When a young woman washes ashore on a Fort Lauderdale beach, Sloan McPherson of the Underwater Investigation Unit is called in to consult. For answers she reaches out to Gwen Wylder. The Miami homicide detective is notorious for being smart, but also hard to work with. After a second body is found, they agree they must work together to find the killer.

I am a total fan of Andrew Mayne. His twists and turns keep me coming back for more. He has well developed characters, forensic mysteries and page turning thrillers which always have me excited to see what's coming next! The only qualm I had about the book is I wished it would have had more underwater investigating otherwise I thoroughly enjoyed this read.

I want to thank NetGalley, Andrew Mayne and Thomas & Mercer for the e-ARC of this book. Opinions expressed in this review are honest, my own and left voluntarily.

One of the reasons I have really liked Andrew Mayne's books was because of Sloan and the UIU. The setting and the fact that she was a young mum and is now trying to juggle motherhood and intense cases in her worklife along with a teenager really interested me. This time though, Sloan barely gets her feet wet and there isn't much mention of her daughter either.

However, Gwen makes an appearance, a socially awkward, abrupt genius who wants something from Sloan. Only thing is, will the price be too high?

Good writing as always, but I feel like this book lost it's way a little bit.

4 stars from me.

Thank you to NetGalley for my ARC. This is my honest review.

Book number 4!!! I love a good thriller when you need a nice cleanse from all the romance books. The book is very different from the first 3. Sloan is the one taking the spotlight in this installment. Scott and George only make appearances. Sloan takes all the risks needed to solve the case while advocating for the victim. This was a great book and a good read. I would recommend this series to someone who likes thrillers.

4 stars!

I came into this book not knowing that it was part of a series, but that did not stop my enjoyment at all. I think this might have aided me because I don't typically like mystery series as I feel like they start to meld together. My main issue was I wasn't completely convinced by the motivations of the killer and I felt like once Sloan figured out who it was the book ended shortly after. Overall, I do think that this was a good time and I'm glad I read it!

Thank you to Netgalley and the publisher for an ARC in exchange for an honest review!

I fell in love with this series from the first book and have enjoyed each new iteration. The last book I guessed the villain pretty much right away, so I was hoping for a bit more cloak and dagger this time around.

Thankfully, Mr. Mayne delivered! I was misled and was kept on the edge of my seat until the end.

While I’m not a huge fan of the current direction of the UIU as a unit (I wanted them to stay independent!), I’m hoping this gets resolved in the next book.

Overall, I’d give it 4 out of 5 thumbs up!

Sea Castle is the fourth installment in the Underwater Investigation Unit series and unlike the other three this one focuses mostly on Sloane as the unit has been broken up. Even though it follows basically the same format at the other three, I still really enjoyed following the investigation into a possible serial killer. Gwen was unlikable but also you could understand why she got to be this way.

While you could read this one as a standalone you would be missing out on some back story. A perfect beach read or just something to binge when you need a mental break, Sea Castle was a solid addition to the series.

I really enjoyed this book. I think it is the 4th in the series and it was my favorite thus far. I loved the addition of Gwen as a character and hope they bring her back again. I also appreciate that they are allowing Sloan to mature as a character. As a therapist the only thing I did not like was that the author denied multiple personality disorder exists. Dissociative Identity Disorder does exist and it is in the DSM. It does harm to spread untruths about mental health issues.
I was given a copy from Netgalley. Opinions are my own.

I’ve read the first and last books of this series and enjoyed each immensely. This one started off a little slow for me, it took a while for me to get invested. Half-way through, I was hooked and couldn’t put it down. This book had more twists and turns than the world’s boldest roller coasters. Every time I thought I knew who the killer was, a quick right turn and I was left feeling bewildered. This happened repeatedly, and I was utterly stunned when the killer was finally revealed. Talk about a wild psychological thriller! Wow!

The main heroine was Detective Sloan McPherson, a strong, intelligent, and respected underwater investigator. She was loaned to the Florida Department of Law Enforcement to aid in some cold cases. Sloan was teamed up with Gwen Wylder, a senior detective with a reputation for being extremely difficult to work with and possibly unhinged. Somehow, McPherson and Wylder managed to form an excellent team and bring down the killer.

This crime thriller was full of action, and the characters and plot were well developed. I would highly recommend this book to anyone who loves psychological or crime thrillers.

I am grateful to Author Andrew Mayne, Thomas and Mercer Publishers, and NetGalley for allowing me the opportunity to review this Advanced Reader’s Copy. This is a voluntary review, and all comments and opinions are entirely my own.

As embarrassing as it is to admit, I think I forgot I had this book. That was after I didn't leap on it right away to read, possibly because I was mildly disappointed by the last book in the series. As I said in the review for that one, it wasn't as if the book was bad; it was just that the case wasn't as exciting to me as earlier stories.

This book, fortunately, course-corrects for me. The case itself is compelling, but even better, the villain behind it all is equally fascinating. And while there was a lot less underwater action this time, Sloan's pairing with Gwen makes up for it. In addition, it adds another layer of suspense, as Sloan often doesn't know if she can or should trust Gwen. And all of this adds up to a story where the stakes are high and the twists are delightful.

MUCH better than the last one

UIU has been shelved for being too effective, although of course that's not the official reason. The team is off doing their own building skills and relationships in hopes that they will shortly be reunited.

Sloan has been seconded to the Florida Department of Law Enforcement where she sits trying not to annoy her boss, a task that is hard to accomplish because law enforcement agencies across southern Florida keep calling and asking Sloan to come take a look at their case. Sloan's lucky intuition would be hard for any desk jockey boss to swallow.

Finally Sloan is paired with curmudgeon Gwen Wylder, a very senior detective who was exiled to the basement when her behavior got too erratic. People would like to can her but Gwen is nearing retirement and her notably high success rate gains her a lot of slack. So she is in the basement looking over cold cases.

Somehow Gwen and Sloan form a working relationship and solve not one but three cases.

No diving this time and no preposterous story lines. I read it almost straight through.

This is the 4th in a series, but the great one I have read.

It is enjoyable and a great thriller!