Rin Okumura is a seemingly ordinary boy living at the Southern Cross Boys' Monastery. One day, however, Rin encounters a boy who has been possessed by a demon. Amidst the struggle, he not only awakens latent powers sealed within him, but also learns that he is the son of Satan! No longer able to stay under the protection of the church and with his very existence straddling the line between human and demon, Rin decides to fight against his parentage and joins the True Cross Order as an exorcist. Now, the teen must attend the True Cross Academy and begin special exorcist training alongside his new comrades all while keeping his identity a secret; but can the son of Satan really become a true exorcist?