I adored this series. Right up until this book, which I'm going to pretend never happened. I can't say I didn't see it coming (in my review of the 3rd book I even said that "Also, Will Henry is headed down a dark path, and I don't think it's one Warthrop is eager to follow him down, so Book 4 had better become a reality.") but oof, it seems such a sudden turn, a sudden betrayal. 
 We're in at least two time periods in this book, though--Will Henry as a teen and Will Henry as an adult, 20 years later, returned on a summons to Pellinore Warthrop's side. Adult-Will's response to everything about Pellinore--remember, the closest thing to a father he has--is revulsion and hatred and bitterness, and it's hard to say where things took that turn. We see Will Henry as a snot-nosed rebellious punk teenager, but it's hard to say what went wrong between them--a broken loyalty, a growing apart, a natural maturation of Will from child to adult that's been shaped (deformed) by all he's seen in Warthrop's basement. 
 At times I felt like there were at least two slightly-different time periods in the past--Will at 16 and Will at 17 or something, it was hard to tell. (Also I had the audio; it's possible the disc was skipping or something.) It was hard to keep track of what was going on because, dang, Will Henry, you've become one of the monsters. 
 Three books, I've been rooting for team Pellinore-Will Henry. This time, it's just Team Pellinore, because Will Henry has revealed himself to have few, if any, redeeming characteristics. While Book 3 (Isle of Blood) was, at its heart, a father-son story, this one was trying to resolve all of Will's relationships with women, for better or worse, and how his heart betrayed him. 
 I'm curious to re-read Book 3, just to refresh myself on the "dark path" I saw Will Henry heading toward, because whoooo boy did he choose a very dark path indeed.