Erkin, a young pharmacist from the north, was orphaned from the war between the Northern Nations and Mormeratta. After making a name for himself in Mormeratta, he is summoned to treat a mysterious “master of the castle” whom no one has ever seen. He reluctantly agrees, hoping it will bring him one step closer to finding the infamous Witch of the Sun who killed his parents during the war. Little does he know, on his quest for vengeance, the witch may have been by his side all along. What will Erkin do when confronted by his sworn enemy turned friend?