The Will of the Empress by Tamora Pierce

I think that this book is another example of the amazing books that Tamora Pierce has written. This book is about 4 young mages, who are also a foster family accompanying Sandraline fa Toren , who is on of the 4 mages, to her lands and, inevitably, to Sandraline's imperial cousin, Berene, empress of Namorn (one of the countries in this series) who does not want the four powerful, but young mages to leave, doing all in her power to stop them. If you are interested in starting this series at the beginning read 'the magic in the weaving' in the circle opens quartet. This book is perfect for 12+ years. It's genre is fantasy.