Erkin, a young pharmacist from the north, grew up without parents because of the war between the Northern Nations and Mormeratta. Despite this, he had earned a good reputation in the newly established Kingdom of Mormeratta. One day, he was asked to take care of a mysterious "master of the castle" he had never seen before. Erkin was hesitant to accept the job since he was unfamiliar with the illness and the patient. But he reluctantly agrees, hoping that it would lead him to finding the Witch of the Sun who killed his parents during the war. Little did he know, his sworn enemy could be the one helping him seek vengeance. Will Erkin be able to handle the truth when he finally confronts it?