When Ashiya begins working part time at the Mononokean, the master Abeno impresses upon him that he should pretend not to see any yokai other than the Mononokean's clients. However, the kind-hearted Ashiya is unable to keep his word, and the yokai won't leave him alone. Based on their surprising strength and numbers, Abeno believes there must be a powerful demon serving as their leader.

When Ashiya hears that Abeno will be going to a pharmacist called the "Kiyakudo" in the Underworld, he asks to go with him. Though Abeno is reluctant to bring a human to the Underworld, he relents when the Mononokean suggests that Ashiya accompany him. Concerned for Ashiya, Abeno forbids him to travel in the Underworld alone, but Ashiya finds himself unable to keep his word again.