The "Medicine Seller" is a lethal and enigmatic occult expert who travels throughout medieval Japan in quest of demonic spirits known as "mononoke" to slaughter. When he finds one of these spirits, he cannot just kill it; instead, he must first study its Form, Truth, and Reason in order to wield the great Exorcism Sword and combat it. He must begin his unusual exorcisms with rigorous psychological analysis and thorough investigation work—an exceedingly perilous step, for he must first confront and learn about the mononoke before he can destroy it. The voyage of the Medicine Seller brings him to an old-fashioned inn where Shino, a pregnant woman, has finally found a place to relax. She was regretfully placed by the owner.