For the three hundred years that the Romanov dynasty has been in power, they have led Russia through an era of unprecedented peace and prosperity, but recent peasant uprisings and a sickly heir have destabilized this once-proud royal family. In a desperate move, the Romanovs have unknowingly employed one of Diva's original Chevalier - whose motives are not to cure the ailing Prince Alexei Romanov, but to create an army of perfect, blood-craving Chiropterans! Using his influence to gain test subjects, this mysterious Chevalier has performed horrifying acts in the name of science, and he now has Hagi, Saya's Chevalier, in his clutches! On the eve of the Russian revolution, it's up to an unseasoned and unsure Saya to save Hagi, destroy the Chiropteran experiments, and track down her murderous twin sister before a horde of warrior Chiropterans are set loose to terrorize the unsuspecting Russian masses! But first, Saya will have to struggle with her conscience if she is to be strong enough to kill those of her friends who have been turned into monsters!