In an alternate universe, the Holy Grail War was won by the Yggdamillenia family. Now two factions with 7 Master-Servant pairs each and 1 extra Servant as the Ruler are fighting to win the Greater Holy Grail.

In an alternate universe the theft of the Holy Grail 50 years previously ushers in a new conflict between the Mages Association and the rebellious Yggdmillennia Family. With the activation of the Greater Grail, 15 Servants are summoned for an unprecedented battle royale in a new Holy Grail War.