This story revolves around Ashton Grace, a delinquent with a brash personality and a rough past.
Ashton lives day to day in an endless, boring cycle of school, beating rival gangs, and skipping on stupid, mundane homework until his 18th birthday arrives, and his life changes forever.
On his 18th birthday, a cursed demon sealed within Ashton awakens, changing the course of his life and even Ashton's unknown future unexpectedly.
To find answers of his existence and to rid of the demonic curse, Ashton must work with Co, an underground exorcist organization that purifies demons lurking in the human realm to rid of powerful devils within the city of Tsurugi.
Now to purify the world of demons and devils, Ashton must also work with Jin Itsuki, one of the top exorcist of Co nick-named Mad Dog, and seemingly the only person who can tame the demon inside of him.
Unexpectedly, of course, that comes with many problems--one with being falling in love with the one man who hates demons the most.
Turning 18 is the worse, ain't it?