A gem hidden behind a confusing title and terrible cover art. 
 Many reviews categorize this book as Fantasy. It is not fantasy. The author could have made it a fantasy, but instead chose to make it realistic fiction. I have seen this approach botched (Here Lies Arthur), but this time it made the story more interesting. 
 If you enjoyed Holes, you will like this book. It has the things I liked about Holes, as well as: 
 * little things you thought were unimportant, that suddenly come together and make you sit up. 
 * a dark conspiracy hiding behind a law-abiding community 
 * parts where the tension is built and held like a Hitchcock film 
 * realistic fiction with a touch of "wait, was that magic?" 
 * a touch of divine intervention ("You were meant to have the ring...") 
 * true love 
 * good research on behalf of the author 
 I highly recommend it. 
 The title makes sense once you have read the book, but it was a poor marketing choice. It sounds as interesting as "The Scary Ghost" or "The Tough Ninja". Even in the book, the characters are not familiar with the archaic term "gard" (castle) and it has to be explained. And then they wonder, "Why would people call the castle perilous?", which is what we were supposed to wonder when we read the title. 
 I have had a hard time relating to characters in other historical fiction (Crispin: The Cross of Lead, The Shakespeare Stealer). The way they think or react is from a different era. Pope overcomes this by having other characters that are much more foreign, so you feel some camaraderie with the protagonists. They find the weird characters as alien as you do, and you realize they are more like you then they are like them.