Mostly Dry-Docked Sloan Does It Again
5 out of 5 stars
Sea Castle is the fourth book in the Underwater Investigation Unit series by Andrew Mayne. And it starts off like any of the other books do – with Sloan doing what she does best. But after the initial search and dive, things take a turn. Especially since things with (spoiler alert if you haven’t read any of the other books in this series) the UIU are limited due to some investigations and red tape. Sloan is now forced to help find who did this on land with the assistance of someone who has been relegated to a back office. Gwen, this someone has similar instincts to Sloan, and some officers believe may have taken those instincts too far.
The story itself was fascinating, dealing with the occult and cult-like leaders. And death. Unfortunately, lots of death. Sloan and Gwen are forced to try anything they can to find this/these killer(s) before they strike again.
I wasn’t sure how I would feel about Gwen when first introduced to her. Still, there was a scene in the car where she’s trying to help de-program the woman they picked up, and for some reason, at that moment, I realized that she was going to be a fascinating character and a good addition to Sloan’s arsenal of people she can call for help.
Sea Castle was a blast from beginning to end, a book that I couldn’t put down.
Book Description:
A Wall Street Journal bestselling series. A deep diving investigator is pulled into the depths of a string of unsolved serial murders in a riveting thriller by the Amazon Charts bestselling author of Sea Storm.
When a young woman washes ashore on a Fort Lauderdale beach, Sloan McPherson of the Underwater Investigation Unit is called in to consult. Sloan’s instinct says murder, but even then, there are too many questions.
For answers she reaches out to Gwen Wylder. The Miami homicide detective is notorious for being manipulative, bitter, a tyrant to her peers, and wicked smart. And she demands something in return from Sloan: fresh insight into seemingly unrelated cold-case murders and disappearances—and a possible serial killer trolling the Florida coast.
As loose ends of the old files begin to come together, another woman disappears. Sloan and Gwen are certain she’s the newest link in a deadly chain. They are determined to track her down before she dies, but they soon find themselves in uncharted waters. And the deeper Sloan and Gwen go, the stranger the case gets.

Sea Castle by Andrew Mayne
Narrator: Susannah Jones
Length: 7 hrs and 57 mins
Series: Underwater Investigation Unit #4
Published by Brilliance Audio on February 21st 2023
Genres: Sea Adventure
Format: Audiobook
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Also by this author: The Naturalist (The Naturalist #1), Looking Glass (The Naturalist #2), Murder Theory (The Naturalist #3), Dark Pattern
Also in this series: The Girl Beneath the Sea, Black Coral, Sea Storm
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