Ten years ago, the Zol Empire conquered the neighboring lands of Aquafa, forcibly merging the two nations. Though the effort was a success, the Zol invasion could not seize Fire Horse Village, where an outbreak of a mysterious deadly disease known as Black Wolf Fever occurred. Since then, the people have believed the illness has been eradicated. At a salt mine overseen by Zol authorities, Van Gansa is a prisoner of war carrying out a forced labor sentence. One night, a pack of spirit-like wolves attack the mine; while Van and a young girl named Yuna are bitten, the two escape as the only survivors. In the official investigation following the incident, the findings indicate that the wolves were carriers of Black Wolf Fever, which led to the swift deaths of the guards and workers. Eager to experience freedom again, Van wastes no time settling down with Yuna in a small farming village. However, Van does not know that he is being followed. Pursued both by those who wish to harvest his blood to cure Black Wolf Fever and those who want to stop those efforts at all costs, Van faces a greater issue plaguing the nation that may spread to countries beyond.