There was once a Holy Grail War waged by Mages and Heroic Spirits in a town of Fuyuki. However, one Mage took advantage of the chaos of World War II to steal a Holy Grail. Several decades have passed, and the Yggdmillennia family, who took upon the Holy Grail as its symbol, defected from the Mages' Association. Furious, the Association sent forces...