In this book, Celaena Sardothien travels to Wendlyn on a mission, but her real goal is to understand her past and her powers. Emotionally broken after tragic losses, she meets Rowan, a powerful Fae warrior who forces her into intense training so she can learn to control her magic. Gradually, she regains her strength and discovers her true identity as Aelin Galathynius, heir of Terrasen.
Meanwhile, in Adarlan, Chaol and Dorian face growing political danger and the return of magic in the kingdom. A new storyline is also introduced with Manon, a ruthless witch whose role becomes increasingly important.
By the end of the book, Celaena fully embraces her identity and becomes stronger, setting the stage for the coming war against the King of Adarlan.