The Holy Grail, an ancient artifact with the power to fulfill any wish, sparks a deadly competition among magi and their legendary Heroic Spirits—servants—in the Holy Grail War. Following a mysterious disappearance of the Grail after the third war, the Yggdmillennia clan claims its possession, causing a clash with the Mage's Association. With only two factions involved, each deploying seven master-servant pairs, the conflict escalates uniquely. As tensions mount and the battlefield fills with summoned warriors, the stage is set for the epic Great Holy Grail War to unfold.