BUT. So much is left unanswered. :( I spent most of the book wondering about the motivation of one particular character, then got to the end and have to wonder about the motivations of lots and lots of (historical) characters. Seriously, a cautionary tale would make so much more sense than what seems to have happened.
AND, the book ends with all sorts of stuff still hanging. In fact, I would go on a limb to say NOTHING has actually been decided. If it's the start of something, fine. But as a standalone, it leaves a great deal to be desired.
WHY did the sword recognize her? Why bother, unless it was important to the story?
WHAT is going to happen with the war? Will any of her brother survive it? If none do, that makes the first point more important - but not in this book.
WHY was there mention of it being okay for the leaders to communicate, but not for others, if the leaders can't? Unless, of course, Sylvi and Ebon END UP the leaders. Then, suddenly, that little conversation will make sense. But, again, that didn't happen in this book.
The king declares that the information revealed at the end will be studied. Fine. But we don't see the results in THIS book. If there's another book, this will, again, make more sense.
SO MUCH that requires another book, but past history tells me there won't be one. Robin McKinley doesn't write introductory books. :(