Celena is the Princess of Eribourne, second in line to the throne behind her elder brother, and supposedly good for nothing other than becoming the beautiful bride of a suitor of her father's choosing. When Celena was a child, her father confined her within the castle's walls, not allowing her to stray too far from his watchful eye. But on the day of her eighteenth birthday, Celena is given a necklace from the castle cook. That night, the necklace and the full moon drag her to a portal that transports the Princess to the warrior tribe of Apogee, located in a world entirely opposite her own -- a world that hates monarchs just as much as its people love bloodshed. Now, the girl who never once believed she was destined for anything greater than becoming a suitable bride, finds herself training alongside the legendary Batair sisters and the leader of Apogee, causing Celena to question everything she has ever known.