The book is about twins who are part of a long line of twins that are part of a prophecy and could bring about the end of the world. One twin is good, the other...not so good. Due to a trick in their delivery, they are each fulfilling the role in the prophecy contrary to their nature. The storyline is interesting, and there are sufficient creepy parts. Some plot points are very obvious, though, and the story does not always read like it is in the time period it is supposed to be set in.
The book did not make it obvious from the outset that this was not a self-contained story, but there is at least one more book, and I figure it is probably at least a trilogy. The lack of resolution was VERY annoying, but I guess the fact that I wanted to know what the ending would be points to the fact that the story was intruiging. Not the best thing I've read lately, but interesting enough.