This book in istself is a 4-star read for me but it's getting 5 because you need to read it first in order to read all the other short stories and books in this series, all of which are fantastic and to which I'd give 6 stars if I could.
I love these two as a couple, and I think where this book lacked for me was that the mystery took center stage and the relationship didn't progress much until the latter part of the book (so if you love plot-driven mysteries, you might actually like this aspect).
My favorite quote of the series does come from this book though:
Warrick: "And the evidence tells me you like to play games. Particular games, at that. Tell me something—how often do you have sex with the same person, on average?"
"Once." Toreth shrugged. "Twice, maybe, if—"
Another fucking interrogation, but what the hell. "If they regretted the first time."
Hah, that's the core of Toreth's personality right there, and what makes him such a great character, and Warrick gets it!
Also, this is self-pubbed online, and it was a pleasure to read such an error- and typo-free book!