The story focuses on a Grail War that is an imperfect replica of the Third Holy Grail War in Fuyuki. Following the conclusion of the third war, an American organization composed of magi independent from the London-based Mage Association obtained data from Fuyuki's conflict and devised their own ritual. Seventy years later, they designated the city of Snowfield as the Sacred Land for this Grail War. They failed to replicate every element of the original ritual, resulting in an imitation that lacks the Saber class and permits the summoning of unusual Servants because the definition of a "hero" has become ambiguous.