Evil spirits definitely exist in this world.
In addition, those unbeknown to the public who banish and control these spirits also exist.
These individuals are called "Exorcists" by those aware of their existence.

What society usually refers to when referring to "Exorcists" are the clergy responsible for mundane exorcisms, but in reality there exist evil spirits who can physically harm humans as well as clergy who fight these spirits.
When referring to these clergy who fight evil spirits, it is logical to refer to them as "True Exorcists".

Kiyoharu is one of these "True Exorcists".
He possesses powerful exorcism techniques different from his peers, these techniques are called "Holy techniques".

The flood of people seeking help from Kiyoharu to acquire his skills is unending, Kiyoharu is now a well-known entity in the world of the "True Exorcists".

However his "True Exorcist" identity is his hidden aspect. His public facade is that of a mundane priest.
An academy nurturing the next generation of clergy "Saint Marianne Girls' Academy" is next door to the church where Kiyoharu lives.
Attending this academy is the pure and innocent Hinata who boasts the ability of prophecy with astonishingly high accuracy.
Hinata's best friend is the half-Japanese girl Lily who aspires to be an outstanding member of the clergy comparable to both of her parents.
The Academy Representative Saki is slightly overprotective and bears the trust of the entire student body on her shoulders.
The story involving Kiyoharu and engulfing the girls he is close to now begins.

[Translated from official website: http://astronauts.co.jp/comet/adebana/story.html]