Ocean of Silver by Mallory Benjamin

Being too powerful can become a weakness…

Scotlind Rumor is finally returning to Lux, except she’s not going home. She’s now a prisoner to the most lethal and powerful Advenians—the Luxian Royals. Scotlind knows she’ll never be free. They are keeping her for a reason—she’s a puppet in a dangerous game. One that’s only just starting to unfold. As Scotlind is forced to play along in order to survive, she prays that the person controlling her strings isn’t the Prince that haunts her nightmares.
Sie Noren must face the consequences of his actions. He betrayed the only girl he ever loved, and now she belongs to his enemy—the Fire Prince—and he only has himself to blame. But when Sie is forced to see Scotlind again after months apart, things won’t end well for anyone, and he plays right into the hands of fate.