Approximately nine hundred years ago—.

There was a peaceful town where humans and yokai lived together. The town was governed by an oni couple.

Though they were yokai, they protected the people and believed in a future where humans and yokai could live hand-in-hand. However, that peace did not last long.

The government forces invaded the town under the pretext that "the existence of yokai brings calamity," massacring humans and yokai alike without distinction.

The town was destroyed in a single night.

The husband barely managed to survive with his comrades, but his beloved spouse was taken away by the government forces.

He spent hundreds of years searching the entire world to reclaim his spouse.

But he found nothing.

No clues, no traces.

Even so, he could never bring himself to give up.

Through the staggering span of nine hundred years, his comrades vanished, eras changed, and eventually, his own soul reached its limit.

And then—.

He was reincarnated in the modern era as a high school student.

Retaining the memories of his past life.

Given a new life, he begins his search for his spouse once again.

For the beloved person he lost nine hundred years ago.

And what is the truth that awaits after nine centuries—?

This is the story of an oni from a fallen town, who continues to search for his beloved spouse across time.