The Winner's Kiss by Marie Rutkoski

Some kisses come at a price.

War has begun. Arin is in the thick of it with untrustworthy new allies and the empire as his enemy. Though he has convinced himself that he no longer loves Kestrel, Arin hasn't forgotten her, or how she became exactly the kind of person he has always despised. She cared more for the empire than she did for the lives of innocent people--and certainly more than she did for him.

At least, that's what he thinks.

In the frozen north, Kestrel is a prisoner in a brutal work camp. As she searches desperately for a way to escape, she wishes Arin could know what she sacrificed for him. She wishes she could make the empire pay for what they've done to her.

But no one gets what they want just by wishing.

As the war intensifies, both Kestrel and Arin discover that the world is changing. The East is pitted against the West, and they are caught in between. With so much to lose, can anybody really win?

This book is part of the "The Winner's Trilogy" series.
Here are some other books from this series: