From the introduction: In the town of Fuyuki a number of artifacts known as the Class Cards that contain the powers of Heroic Spirits have started to appear. They seem to be based on the system of the Holy Grail War a competition that was dismantled a decade ago. To investigate the artifacts the Mage’s association has sent a number of people to retrieve the cards so they can study them and attempt to divine their origins. You begin a day after the Kaleidosticks abandoned their old masters and chose new ones.