I wasn't quite prepared to give ths four stars, but it was better than 3.5. If there had been a 3.75,, that would have been perfect.
The plot is nicely complex, with several unexpected twists and turns. Again, it's easily compared to Dan Brown's blockbuster The DaVinci Code, but this is by far the superior book. Plot, characters, everything, head and shoulders above.
Recently retired Justice Department agent Cotton Malone is settling into his new entrepreneurship as a bookseller in Copenhagen when he's pulled into a deadly quest to locate the long-lost treasure of the Knights Templar. Much of the action takes place in the environs of Rennes-le-Chateau in southern France and incorporates the same background "facts" as the Brown book, generously borrowed from Holy Blood, Holy Grail.
The extensive borrowing became annoying to me after a while, but probably only because I've read HB/HG several times -- I have my own tattered copy -- as well as some of the fan fiction/fact-tion that grew up around it and some of the source material. Berry goes into a great deal of detail, maybe more than he needed to. That pulled the rating down for me.
But the writing is good and the characters very well done. I like books where I can easily imagine the characters as real -- I can hear their distinct voices in my mind as I read, see their actions and even facial expressions -- and Berry accomplished this. His characters are also varied, they have baggage and doubts, and they aren't perfect.
There were a couple of small bloopers that didn't really impact my enjoyment of the story, but did bring me out of the action for a while and left me alert for others rather than being completely absorbed.
The first blooper was that Malone didn't check his rental car for a tracking device. The second was that the back window of that rental car was shot out, but he continued driving through the rain storm and never mentioned anything about the car being wet inside.
The ending veered into the too good to be true end of the spectrum, and I wasn't entirely comfortable with some of the moralizing, but it wasn't bad.
I have a couple more of Berry's books and may take a look at them when I have time.