New York, in the 1920s, a horde of demon began to appear out of nowhere to terrorize the citizen. The demon lord Aion is back with a great purpose, in order to get more power, he has to steal the gods power to make himself invincible. In order to do that, he needs the powers of 7 Apostles (Mary\'s chosen ones) around the world to make his dream come true. He has his eye set on Azmaria Hendrik, who\'s one of the Apostle. However, a sister from the Mary Magdalene foundation Rosette Christopher along with her assistant Chrno, a demon from the dark world have a mission to protect her from Aion at all cause. Rosette still seek the whereabout of Joshua, her long lost brother however she learned that her brother is on Aion side by giving him the powers of the demon. Will Rosette and Chrono find Joshua before it\'s to late??? Will they protect Azmaria from Aion???