Princess Charis Willowthorn is the dutiful sword of Calera. Raised to be ruthless and cunning, her only goal is to hold her war-torn kingdom together long enough to find a path toward peace with their ancient foe Montevallo, even if the cost is her own heart. When violence erupts in the castle itself, nearly killing the queen, Charis must assume her mother’s duties and manage both the war and her kingdom. But as an unseen enemy begins sinking Calera’s ships, Charis realizes a threat much greater than Montevallo is coming for her people. So she forms a plan. By day, she is Calera’s formidable princess intent on forging an alliance with Montevallo. By night, she disguises herself as a smuggler and roams the sea with a trusted group of loyalists, hunting for their new enemies. And through it all, there's the one boy she can't have—who guards her life, but steals her heart. But her enemies are much closer than Charis realizes, and her heart isn’t the only thing she has left to lose.