At True Cross Academy, Rin Okumura unknowingly comes across the first signs that something is amiss; ordinary people have been gaining the ability to perceive the invisible creatures that roam the human realm, Assiah. While Rin sees this as an opportunity to make a new friend, his twin brother, Yukio, is more burdened than ever. Swamped with his education, exorcist duties, and teaching position, Yukio has remained si...