First, a disclaimer: I entered this series with this book, so this was my first venture into this world of Vigilant Lock. I only found myself lost in that there were a lot of references to code names, but the author provided enough of the important backstory to understand why certain characters despised each other or manipulated each other the way they did. Very entertaining read. It read like a good government conspiracy/black ops book with a paranormal flavor. The characters are unique and work well together. At times, I had a hard time remembering that Harmony was female. I am looking forward to going back and reading the other installments and getting to know this dynamic duo of Harmony and Jessie (as well as the other team members).

A fantastic fourth instalment in the Harmony Black series, and the strongest to date, Craig Schaefer has done himself proud with Cold Spectrum.
Adrift from their chain of command and not knowing who to trust, Harmony and the rest of her team are desperate to learn more about Cold Spectrum. Betrayed by their own agency, and framed for a crime that didn't happen, they need to be on their best form in order to escape the powerful people gunning for them.
I don't want to give anything away, so I'm not going into more detail, but Schaefer has said that he plans stories far in advance, and some of those threads start to come together in this novel. The Harmony Black series should be read in conjunction with the Daniel Faust series to fully 'get' everything, but if this is the first one you try, you can always go back.
A very enjoyable urban fantasy romp, reminiscent of Jim Butcher's Dresden Files series, but also totally different. My only complaint is that I now have to wait for the next one.
I received this copy from the publisher via NetGalley in exchange for an honest review

Harmony, Jessie, and friends are in the wind as they aren’t sure who they trust at this point. However, they are set up by those in charge when a job goes wrong, and they are now on the run as traitors and fugitives. Finding new friends and new enemies, they must find a way to get back their reputations without losing their lives, and as they are fighting the infernal, that is a huge task. I absolutely adore this series. Not only is this book well-written, it has great characters, has non-stop action, and is just so much fun. I love the interactions between the characters, especially Harmony and Jessie. They have such a great friendship and that is particularly shown by events in this book. The plot has gotten a little convoluted and complex, but the book was so much fun, I can forgive that. It is fiction after all. This book has taken an interesting turn, and I can’t wait to see where the author is going to take us next. If you are a fan of this series, you will love this book. If you are a fan of urban fantasy and haven’t tried this series, do so because it is so worth it! Highly recommend! Thanks to NetGalley and 47North for the e-copy which I voluntarily reviewed.

Finally the mystery of Cold Spectrum is solved. I liked that a member of the cold spectrum team was a part of Vigilant lock and see Caitlin included in this book. I thought this was the best book in the series. I always enjoy when characters are backed in a corner and have to come up with some kind of scheme to get out of it. Looking forward to more great books in this series.