Divided — Emma L. Adams

Ada is gone, taken by a group of magic-resistant warriors with a grudge against the Alliance. Kay is stranded on Earth, with no way to reach her. But he won't accept that Ada is lost. Ada refuses to resign herself to her fate as a weapon of the Stoneskins. Tapping into her own magic might be her key to escape, but now she's in an unknown world, far beyond the reach of the Alliance. And the tyrannical, dangerous StoneKing has his eye on her -- and her magic -- for reasons she never could have seen coming. Kay puts his job, and his life, on the line to get to Ada. But with powers shifting inside and outside the Alliance and an old enemy waiting in the shadows, the countdown to war has begun…