** spoiler alert ** This is probably one of my favourite books in the series, because its the first book where things aren't a stand-still and actually change.
Like with Georgina always trying to protect Seth from the whole Succubus thing which was part of why they split up. But in this book she decided that it was worth it because LOVE was worth it.. they can't change what she is but they can change the way they go about it.

And the other change that hasn't happened in the books until now is Seth finally realizing that by being and marrying Maddie he is not giving her the right kind of love -- the kind he only feels with Georgina. I think it was only after him rescuing G from the dream world that things finally made sense to him. He realized that he would rather be with nobody than with someone who isn't Georgina.
Then of course the end with Seth saying Letha. Her real name then the question is how did he know that? The logical answer and the only one I can come up with is that he is a reincarnation of her husband and that maybe the whole contract thing is not to do with hers, but maybe somehow her husband made a contract so that one day their souls would find each other again when they stop making mistakes.

I do think Carter and Jerome knows something about this contract and Seth/Georgie thing which they can't talk about. I think more to do with Carter than Jerome because he has mighty been interested in their relationship ever since he came to town.. which is definitely suspicious behavior and with each book we get hints a little bit as to what his agenda is.
I think in the last book we will finally have all the answers that we have the questions to.

Now we just have to wait until Sept 2011 :(