Demonic activity worldwide has significantly increased due to the involvement and corrupt practices of the Illuminati. To combat the unnatural influx of demons, the Vatican Headquarters decides to hold the annual Exorcist Certification Exam early and allow for as many exorcists as possible to take up the mantle. Straight from the Vatican, one of the most powerful exorcists, Lewin "Lightning" Light, arrives at True Cross Academy to help prepare the students for the exam. The ease and mastery with which Lewin performs exorcisms quickly impresses Ryuuji "Bon" Suguro, who has lost his ambition to continue his studies, and Lewin surprisingly accepts him as his apprentice. Amid the worsening situation, twin brothers Rin and Yukio Okumura are sent to locate the recently missing exorcist Shura Kirigakure, who seems to be chained to a decades-long contract with a powerful, immortal demon hiding in Aomori Prefecture's dangerous, snowy mountains.

Based on the one-shot manga .

In present times, Gods and Demons coexist together with Humans after the door between each of these worlds had opened. Tsuchimi Rin is a normal young high school student attending Verbena Academy, spending his days living peacefully with his childhood friend Kaede. Unexpectedly, one day the King of Gods, the King of Demons and their families move into be Rin's next door neighbors. Apparently the daughter of the Gods, Sia, and the daughter of the demons, Nerine, are both deeply in love with Rin after having met him in the past. Along with his playful friendship with upperclassmen Asa and his encounter with the silent but cute Primula, Rin has much on his hands dealing with the affections of each of these girls. Based on the eroge by Navel.

One summer vacation, Ruka meets two boys, "Umi" and "Sora," whose upbringing contains strange and wonderful secrets. Drawn to their beautiful swimming, almost more like flying, Ruka and the adults who know them are intertwined in a complex mesh... Meanwhile, an unexplained anomaly is occurring all over the world: fish are disappearing. Thus begins a marine adventure of boys and girls to captivate all the senses!