A part of me wants to give this book 3 stars, but I just can't. Why not, you ask? Well...
I realized very early on while reading that this book wasn't going to be what I expected (or wanted) it to be. I wanted a DaVinci Code/Historian type thing, a fast-paced thriller none-the-less full of research and deep mythology. Instead it was a run-of-the-mill horror story that echoed the plot of some movies I've seen. Yes, there were plenty of references to Paradise Lost, and yes, there's a demon, but I felt like I might have gotten more actual demonology from a UF series.
The writing itself was decently done, but the storytelling was problematic. Despite the author's use of the present tense, and a looming deadline--which if missed, all would be lost--there was no sense of urgency in either the writing or the protagonist's actions. I mean, he's in Florida, and, realizing he needs to get to Canada (at this point there's probably two days left, though that is an estimate because the author never makes note of the actual time/date even though it is so important), the protagonist decides to drive a car rather than take an airplane. That's more than a 24 hour drive, trust me, I've done it. And he even stops to play tourist at Niagara Falls on the way, even though his daughter's soul--supposedly the only thing he cares about--is in jeopardy. What the hell.
The entire plot revolves around a videotape that contains proof that demons exist. Everyone in this book seems to think that if released, this evidence will change the whole world. I think that's really naive. Most people these days wouldn't believe it's real, even if it's verified up, down and sideways. Or they wouldn't care either way. The only people who would find such a thing valuable are the people who already believe, or want to believe. So this world-shattering item that is the focus of the story is actually pretty lame, and makes the whole journey seem random and pointless--or at least, only significant for the protagonist and his family.
And then there's the ending. The protagonist's dead best friend suddenly returns as an angel to save the day, he gets his daughter back, and the message is that love can overcome evil. Deus ex machina + trite = Do. Not. Like.
Conclusion, in a word: Disappointing.