After the end of the Unification War, administration of the country was split between the Emperor, the Prime Minister, and five dukes. However, over the years, three of the dukes were killed for treason, with Diese and Ray Dawn being the remaining two Dukes. In the present, Marlya and Free are on patrol in preparation for the tenth anniversary of the end of the Unification War and stop a new artificial Zern I fairy that malfunctions after being sabotaged by an unknown party...