Approximately 20 years after Unlimited Blade Works. Angra Mainyu has been fully excised from the Holy Grail and its systems meaning it is no longer corrupted. To test its systems and ensure that they once again properly the grail selects 7 masters to compete in a 6th Holy Grail over London.

20 years after the 5th Holy Grail War of Fuyuki has concluded, the grail has yet to grant anyone a wish. A purpose it must and will fulfil. Summoning a Ruler in its place, 7 masters are selected to fight once more under their dutiful eye. (This story runs concurrent to Fate/Stay Night UBW and Fate/StrangeFake.)