Mirai goes after a perverted youmu with an eye for human girls. When it sprays Mitsuki with its stink juice, the Literary Club must band together to defeat the powerful--and horrendously stinky--youmu!

The Calm is coming. This is a dangerous time for youmu since it is when their powers grow weak. But what does that mean for the ultra-rare half-youmu, Akihito? And Miroku seems to be up to something. What does he have up his sleeve?

Now that Akihito and Mirai have been reunited, they must work together to defeat Beyond the Boundary’s core. But what will happen to Mirai and Akihito once it has been defeated...? Will either of them survive?

This episode takes place two years prior to the anime series and begins when Hiroomi receives a request for a job from his older sister Izumi: to subdue the invulnerable half-yōmu Akihito. Hiroomi's younger sister, Mitsuki, encounters a dark silhouette in the street on her way to follow Akihito and her brother.