Sinclair O'Malley Meets Her Match. I've said in reviews of earlier books in this series that Sinclair O'Malley is an even more bad ass Jack None Reacher, and this book is yet another example of this. And yet, an interesting wrinkle here is that when Sinclair has to keep her enemies close... it turns out one of them in particular is actually just as badass as she is, and is damn near O'Malley's equal in pretty well every way - a very yin/ yang situation going on here, which was pretty awesome for LeDuc to include. You'll never see Child doing that with Reacher, and indeed very few characters of this level of badassery ever get that camaraderie with a genuine yet darker equal. Thus, it introduced an interesting dynamic to the usual "beat the bad guys into submission" action trope. Also, with starting out featuring a different character altogether and having this particular character go through an entire development arc through this book, again LeDuc manages to craft more interesting wrinkles and make this series so much more than just "good guy is better than everyone".
Mostly centered in the Miami area, the trip to beautiful lush Thailand is well done - and an interesting pairing with reading Sara Och's The Resort, about suspicious deaths at a remote Thai resort, when read close together.
Overall yet another excellent entry in this series, though it does follow on almost immediately from its prior book and has several references to at least one other book earlier in the series (Painted Beauty, book 2 in the series), so for those who can never have any spoilers at all... go back and read those books if you haven't yet. You'll get awesome stories and be glad you have this one when you get done with them. :)
I, for one, am hoping we get Book 5 in this series with a much shorter gap between the books. :D Very much recommended.