High schooler Aoi Mashiro moved from home six months ago, but her recent breakup has made her want to return to tell off her ex-boyfriend. In need of money for a train ticket, she steals two hanging scrolls from her grandfather's attic and takes them to be appraised at an antique shop in the heart of Kyoto's Teramachi Sanjou shopping district. Little does she know that a fateful encounter awaits her during this visit. Upon entering the shop, Aoi is greeted by Kiyotaka Yagashira, the owner's grandson and a graduate student at Kyoto University. Nicknamed Holmes for a pun involving his surname, as well as for his incredible deductive skills, Kiyotaka inspects the scrolls that Aoi brought with her. Based on the items she selected to sell, Kiyotaka senses that Aoi possesses great intuition not unlike his own. Seeing her potential and sympathizing with her story, Kiyotaka offers Aoi a part-time job so she can earn the required money herself. Aoi and Kiyotaka begin working together soon after—not only within the antique shop, but also around town whenever the locals ask for help with their various problems. With Kiyotaka's deduction and Aoi's intuition, no case is too tough for this modern-day Holmes and Watson duo!

At the end of season 2. Yuuri defeats Shinou, but since Shinou had been defeated, Yuuri and Murata could no longer go to the Shin Makoku. However, because Yuuri had fought and defeated him, his powers had surpassed that of Shinou's, resulting in him being able to rely on his own power to return to Shin Makoku. After the ceremony at the age of 16, Yuuri slowly begins to discover that much has happened while he was away. The ten officials of the noble family have decided to make Wolfram the next Maou, but now that Yuuri has returned and taken back his role as Maou, complications arise when one noble disagrees with Yuuri returning to the throne. In addition, an ancient secret society that threatens the peace of both humans and Mazoku has risen, and a fight for the throne that now leaves the nobles wondering who is the legitimate Maou.

In an attempt to turn his floundering career around by compiling one hundred ghost stories, struggling author Momosuke Yamaoka roams through Edo-period Japan searching for material. During his travels, the young man wanders deep into the mountains, where he encounters a monk named Mataichi. Failing to heed the monk's advice to turn back, Momosuke presses forward and soon witnesses a murder carried out by Mataichi and his two associates. As it turns out, Mataichi's gang also investigates paranormal incidents—aiming to make those in the wrong pay the ultimate price. Continuing to seek out subject matter for his stories, Momosuke repeatedly crosses paths with the trio of outlaws, becoming increasingly involved in their schemes each time. As the author strays further toward the world of darkness, he grapples with both the morality of the group's actions and the line between humans and the supernatural.

During a blizzard, Masayuki Muroi's old high school friend pushes him off a mountain to certain death. However, Masayuki survives the fall and escapes to safety thanks to Yuki-Onna, the spirit of a beautiful young woman who is said to lead men to their demise—but all she asks in return is money. Eleven years later, Masayuki has lived a successful life, having gotten married and amassing a great fortune. But when his company collapses and his wife cheats on him, Masayuki retreats to the city where Yuki-Onna once saved him, and he reconnects with her by offering her money and tasty meals. While Masayuki recovers from his misfortunes, another one knocks on his door: his ex-wife is found beaten to death, and now only Yuki-Onna—who cannot reveal herself—can corroborate his alibi. With no one to turn to, Yuki-Onna enlists the help of the spirits' God of Wisdom, Kotoko Iwanaga. Revered by the various spirits that wander the earth, Kotoko uses her extraordinary wits and cunning to solve all quarrels they may have. In her duty to protect spirits and humans from colliding, Kotoko drags along her immortal boyfriend, Kurou Sakuragawa, and promises to prove Masayuki's innocence without exposing Yuki-Onna's existence.