There is a good, intriguing story deep down in "The Firefly", and Mr. Deutermann does a good job throwing in enough twists at the end to make the journey worth taking, but he takes the very, very scenic route to get there. There are long stretches in this book of nothing but bureaucratic jostling and protocol discussions. Of course, procedural dramas can have their own appeal, but the notion that this is "a top-notch thriller" — as is screamed at you from the blurb on the cover — seems to take just the actual action into account, and not the lengthy jurisdiction fighting between agencies that takes up a cool one-third of the read. Many times, it feels like excess details are thrown in for the author's sake, not the reader's benefit.
There is essentially one developed character — Swamp Morgan — and even that is generous; we know he is divorced, but it's mentioned more in passing as a way of reminding you that he is a human. Literally every other character, including the main villain Heismann and the secondary protagonist Connie Wall, feels cardboard and underdeveloped.
Beyond that: the big twist at the end feels absolutely, positively absurd. For a book with a sometimes extreme dedication to realism — specifically, how things get done in Washington — to tack on the big twist at the end felt like a complete 180 in believability. It's fiction, yes, but if you have established yourself as operating in a realm of the normal and plausible, you must operate in that realm from stem-to-stern. This book fails to do that.
Credit Mr. Deutermann for an interesting villain, a unique storyline and moments of thrill, but "The Firefly" fell flat for me in many regards.