Balsa the spearwoman is a wandering warrior, who takes on the task of saving lives, in atonement for a past sin. On her journey, she happens to save a prince, and is tasked with becoming his bodyguard. And he is going to need one, for his own father, the emperor, wants him dead.

This is a 10-book series with multiple side-stories and a cookbook; the first book (Guardian of the Spirit) has been adapted into an anime, the first two books have been adapted into manga, and the entire series has been adapted into a live-action drama. The series follows Balsa and the prince, Chagum, as they navigate threats both supernatural and political.