The Medicine Seller is a deadly and mysterious master of the occult who travels across feudal Japan in search of malevolent spirits called mononoke to slay. When he locates one of these spirits, he cannot simply kill it; he must first learn its Form, its Truth, and its Reason in order to wield the mighty Exorcism Sword and fight against it. He must begin his strange exorcisms with intense psychological analysis and careful investigative work—an extremely dangerous step, as he must first confront and learn about the mononoke before he even has the means to defeat it. The Medicine Seller's journey leads him to an old-fashioned inn where Shino, a pregnant woman, has finally found a place to rest. The owner has reluctantly placed her in the last vacant room; however, as she settles in, it quickly becomes clear that the room is infested by a lethal band of mononoke, the Zashiki Warashi. With his hunter's intuition, the Medicine Seller begins his investigation to discover the Form, the Truth, and the Reason before the Zashiki Warashi can kill again.

Torako Koshi is the epitome of perfection. With her peerless beauty, top-notch grades, and position as student council president, her popularity in school is unrivaled. However, she harbors a dark secret—she was a delinquent back in middle school—and this is something she conceals to the best of her abilities. Unfortunately, when she meets the mysterious deer girl Noko Shikanoko, Torako's hidden shame is constantly on the precipice of being exposed due to Shikanoko's rather weird antics. To maintain the reputation she worked so hard for, Torako must go along with Shikanoko's whims, even going so far as to become president of the newly established Deer Club. All her efforts will be rewarded if she can prevent the menacing doe from accidentally blurting out damaging details about her personal history that will undoubtedly unleash Torako's greatest nightmare.

Tooru Kirishima's notoriety is spread far and wide in the underworld. He is most commonly known as The Demon of Sakuragi—a man who is not afraid to resort to violence if deemed necessary. After almost jeopardizing a peace treaty, his boss tasks him with the most difficult job he has ever had: taking care of seven-year-old Yaeka Sakuragi—the boss' precious daughter—so that Tooru understands what it means to be responsible for another life. At first, the two do not seem to meet eye to eye, as Tooru has no clue on how to communicate with Yaeka, and the young girl is not used to expressing her emotions. However, as time goes on, they come to understand each other despite their differences. The fearsome right-hand man of a yakuza boss and the child he must protect are about to learn that family is not always bound by blood.

Princess Anisphia Anis Wynn Palletia has always dreamed of flying through the sky, even though the people of her kingdom consider it a silly ambition. Also at odds with her goal is the fact that Anis is incapable of using magic despite her noble status. Refusing to give up so easily, she renounces her right to the throne, and focuses on developing magicology by combining various resources with knowledge from her previous life on Earth. Due to Anis' nature, responsibility for the kingdom's future is passed onto her younger brother, Algard. Pushed into a political marriage with Euphyllia Magenta, a girl he hardly knows, Algard rebels by spending more time with a commoner girl than his fiancée. After Euphyllia tries to intervene, Algard publicly calls off their marriage and denounces his ex-fiancée as a bully. After crashing into the banquet where Algard makes the announcement, Anis rescues Euphyllia on the flying broom she is testing. She decides to make Euphyllia her assistant, which the other girl reluctantly agrees to. Although their partnership appears random at first, Anis has an ulterior motive for wanting Euphyllia's company.