The Mononokean's job is to exorcise yokai living in the mundane world and send them back to the Underworld where they belong. Master of the Mononokean Abeno Haruitsuki, his employee Ashiya Hanae, and Fuzzy the yokai travel to the Underworld to perform a job for Abeno's boss, the Legislator. Together they help the Legislator with his work, but when Ashiya makes a mistake, he ends up delivering a document to the Executive, one of the top three individuals who govern the Underworld with the Legislator. Who is the Executive--?

Ashiya is sent to deliver a scroll to the Executive at the Legislator's request. On the way, Ashiya runs into a yokai who looks like a giant beast. He attempts to flee, but when he learns the yokai is more considerate than he looks, he is relieved. After finding a lost object for the yokai, Ashiya hitches a ride on the back of the yokai to the Executive's Birdcage, since they happen to be going to the same place. In reality, this yokai is--

A yokai named Egen is scheduled to visit the mundane world. Egen, who dreams of establishing a school in the Underworld, will be observing Abeno and Ashiya's high school for a limited time. Ashiya does his best to help Egen. However, Abeno's foul mood leaves Ashiya bewildered. There's something bothering Abeno about Egen's visit, but Ashiya is completely unaware of what that is--

Innocent fox yokai Yahiko finds a cute little yokai in the mountains. Yahiko brings the yokai home and names her Kinako. Yahiko dotes on Kinako, and she grows fond of him. However, Kinako is too weak to remain in the mundane world and will eventually disappear. Wanting to save Kinako, Yahiko asks Abeno and Ashiya to exorcise her, but Kinako and Yahiko find themselves at odds when she refuses to go without Yahiko, but Yahiko can't return to the Underworld. Ashiya suggests a compromise--

Framed for robbery, Fuzzy is taken to "White Sand Prison," the residence of the Justice, another one of the Underworld's top three like the Legislator. Ashiya, who has come to the Underworld with Abeno to argue for Fuzzy's innocence, is shocked to discover the Justice's surprising true identity. Meanwhile, Abeno realizes another yokai is involved in the incident: the Executive, another one of the top three. The human-hating Executive is very displeased that a human is working for the Mononokean, a shop that has deep ties to the Underworld. And through the Executive's scheming, Ashiya and the Executive come face to face...

Ashiya's friends Saga and Fushimi invite Ashiy and Abeno on the photography club's overnight trip. Since the incident with the Executive, Ashiya has been able to detect yokai at a distance. However, he still hasn't mastered that skill, so Abeno uses the overnight trip to develop Ashiya's detection ability. Yahiko is invited along to help, but a prank he pulls on Ashiya draws out another one of his latent powers--!

The Legislator suddenly shows up at the Mononokean. Angered by the Executive's harsh treatment of his subordinate and employee of the Mononokean Ashiya, he has made a bet with the Executive and wagered Ashiya's banishment from the Underworld. However, Ashiya himself is hesitant about re-entering the Underworld... Meanwhile, Abeno and Ashiya's classmate Fujiwara Zenko's priest father has been hired by the president of the neighborhood association to investigation a location where a ghost has allegedly appeared, but--?

"For just one day, I want to become human and dance with them at the bon festival dance." Ashiya and Zenko bring yokai Keshi to the Mononokean where they work together with Abeno to disguise her as a human so they can enjoy the Bon festival dance together. After granting Keshi's wish and sending her back to the Underworld, Abeno collapses from exhaustion and falls asleep. Abeno had just finished a job for the Executive, which he kept secret from Ashiya. Believing it's his own fault Abeno pushed himself beyond his limits, Ashiya feels responsible and worries for Abeno's wellbeing.

Ashiya's mother suddenly falls ill and is taken to the hospital. Ashiya asks Abeno to take him there and discovers yokai Aranaki haunting his mother. When he hastily removes Aranaki, his mother begins to feel better, but unable to see the yokai, she looks puzzled. Ashiya is surprised to learn similar incidents once occurred with his missing father Sakae. Meanwhile, Abeno is listening outside the hospital room. He recognizes the name Ashiya Sakae--

Abeno travels to the Underworld to investigate Ashiya's father Sakae, but he's unable to find any conclusive information. The cultural festival at Abeno and Ashiya's school begins, and the two are assigned to promoting their class' cafe. They run into Zenko, who has lost track of Yahiko. After catching the mischievous Yahiko, Abeno agrees to play with him. When he casually asks Yahiko about Sakae, Abeno gains new information from him--

Komon hires Abeno and Ashiya to exorcise the five bird yokai they've been taking care of. However, because the youngest yokai Chungo is unable to fly and unlikely to be able to handle living in the Underworld, he'll be staying with Komon. Komon nearly falls from the bridge where the yokai practice flying, but is pulled back up to safety by Chungo, who is supposedly unable to fly. Abeno realizes something is amiss. Why was Chungo pretending he couldn't fly--?

After hearing about the human formerly employed by the Mononokean from Komon, Abeno decides to confirm the yokai's story. The Legislator tells Abeno there may be still be some record of him at White Sand Prison. Abeno enters White Sand Prison and finds some possibly relevant documents, but written in them is... Meanwhile, Ashiya arrives at Zenko's family's temple to discuss a yokai problem, where he coincidentally hears from Yahiko that he's met Ashiya Sakae before--

After a discussion with Zenko, Abeno and Ashiya head to a shrine where a yokai is rumored to appear, and Ashiya is suddenly possessed by one! Sasa the yokai has been trapped inside a tiny shrine for many years by a golden-eyed and golden-haired human with the ability to use his "influence," which allowed him to overpower the strongest of yokai. Sasa reveals their evil intentions when they see Abeno, a human who looks quite similar to the one who robbed them of their freedom. Abeno uses his influence to knock out the possessed Ashiya, but it only increases Sasa's hatred... Later, Ashiya regains consciousness, but his unusual behavior and cold eyes remind Abeno of another person--