The Last Heir (The Bohvian Chronicles #1)

At the age of seven, bastard born princess Zovia lost everything to a despicable tyrant; her family, her people, and her nation. When she fled the palace she swore nothing but vengeance and bloodshed be brought upon the conqueror and his kin by her own hands. Fifteen years later a threat on the mad king's life sends Zovia -a now newly ordained knight- on her first assignment: return to the lands she once considered her own and protect the man she promised to kill.
Meanwhile, the Queen of the Sea's daughter, Zephyrine, sets sail on yet another seemingly ordinary voyage until out of the blue she and her crew are held hostage by a group of infamous pirates who uncover a shocking revelation about her. She soon discovers that in a kingdom full of scheming, betrayal, and deception, a much greater threat than war looms.
Between the two of them, the somewhat princesses must navigate the dangers of stormy seas, empires on the brink of warfare and the epitome of evil itself, but they have to tread carefully because in the world of kings and crowns: anyone can betray anyone.