This is one of those books that it's probably best to come to knowing nothing at all about the plot. That way, none of the surprises are spoiled. But since you'll probably read the dust jacket no matter what I say, I might as well add my little bit.
The setting is Northern Ireland in the 1970s. Not a happy place, and this is not a happy book. I haven't read a book in which the hero (not to mention some of the other characters) gets beaten and tortured so often. And anyone can die at any time. Don't say you weren't warned.
The plot functions on two levels. The conflict in Ireland is mirrored in the conflict between the Fey (you know who they are) and the Fallen (angels, that is), but it's the human conflict that gets the most page-time. William Kelly, known as Liam, doesn't know his true father's name, so he doesn't know that he has certain abilities. They begin to show themselves during his various prison sentences (he's innocent, but that doesn't matter in the Ireland of the time). And it turns out that he's a pawn in the other conflict, too. It's complicated, but Leicht does a fine job of making it all hang together.
The writing is smooth and assured, and the plot is thriller-oriented with plenty of action. You shouldn't think that means the characters are neglected. They aren't, and they're all vivid and well rendered. Since this is obviously the first book in a series, there's more to look forward to from Leicht, who I hope is working on the sequel.