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--
Rather than studying a 
single subject all day,
Anstatt den ganzen Tag
ein Fach zu pauken,
No estudian un solo tema al día,
Ao invés de estudar um
único assunto por dia,