Set in a fictional country called Daeho that does not exist in history or on maps, it is about the love and growth of young mages as they overcome their twisted fates due to a magic spell known as the "alchemy of souls", which allows souls to switch bodies. It follows the story of an elite warrior named Naksu, whose soul is accidentally trapped inside the weak body of Mu Deok—Jang Uk's servant from a noble mage family. Jang Uk returns to the proper path in life after meeting the unrivaled assassin.