In the Kingdom of Audria, Princess Julia must choose a guardian knight at her coming-of-age ceremony. In her past life, she saved and trained slave boy Leo, chose him—only to be betrayed and killed by him and her sister Chloe. Reborn on the ceremony day, Julia rejects Leo and chooses Kane—the knights’ despised “Grey Mouse,” who seems sloppy, lazy, and mediocre with a sword. In truth, he is the hidden “Shield of the Kingdom,” the last dragon slayer alive.