The Beast With Silver Eyes. The Red Slipper Series, #3

Forced to accompany a childhood tormentor on a journey to the seaside, Keela is thrown into a situation that seems bleak and disagreeable. She could never expect that from this traumatic and horrifying journey, she would find friendship with man who could potentially steal her heart. A deposed, crownless King, with few aspirations and a history of apathy and idleness, Edrick is making his own journey, grudgingly fulfilling an unwanted obligation in order to help prevent disaster for the great nation of Yvrem.
After having to beseech a former enemy of his people for help, he is entrusted with a rare, silver-eyed creature, and given a straightforward assignment. It seems a simple enough request, except for the string of mysterious deaths that follow in his wake. Adding to that, his encounter with Keela presents another predicament for the young royal. He can follow orders or he can follow the girl. Either of which will lead them both into trouble.