After a malfunction on the ark, Allen Walker finds himself thrown hundreds of years into the future. Stuck in an unknown age, and forced to make a new life for himself, he soon discovers that he lacks many things besides knowledge in this strange new time. In this age of heroes, how will a child, who has been trained since youth to be a soldier for the Holy War, live?

Allen Walker needed a break from the drama that was his life. What he needed was some well deserved vacation time. Too bad exorcists don't get any sick days. So, taking a page out of a demonic general's book; Allen left a vague note and disappeared off the face of the Earth... well, more like dimension. Meanwhile... A new serial killer arises...

A suspicious amount of Akuma's are appearing in Japan, specifically, near UA. In order to combat them, the Black Order sends its best Hero, Allen Walker in as a transfer to class 1-A. However, Allen doesn't seem like the angel he resembles so much. Why does he know so much about quirks? About the world before quirks? About Akuma? And why does he insist he's quirkless?