The three important groups, the Empire, the Vatican and the Order of the Rozen Kreuz, are always in conflict. The Empire is on a country called Methuselah and the race is called Vampire. There is conflict with the Vatican for the difference of races. The protagonist is a priest called Peter Abel Nightroad, who travels through the countries as a representative for the Department of Foreign Affairs in Vatican. However, he also belongs to a secret agency of the Vatican known as "Ax", a Special Operation Group controlled by the Cardinal Catherina Sforza, secretary of the Deparment of Foreing Affairs. His encounter with a young girl called Esther will determine the struggle and survival between the human race and the vampires.