The plot tells of the Holy Grail War, mistakenly copied from Fuyuki’s Third Holy Grail War. After the end of the Third Holy Grail War, members of a magical organization from the United States, independent of the London Association of Magicians, collected data about the Holy Grail War in Fuyuki and plan to begin their ritual. After seventy years of planning, as a Sacred Land for conducting their own Holy Grail War, they selected the city of Snowfield, California, north of Las Vegas. The surrounding forests, swamps, valleys, and deserts make the location favorable for performing the ritual.
However, they were unable to reproduce every aspect of the ritual successfully, which led not to a full-fledged Holy Grail War, but only an imitation. For this reason, the Saber class was lost, and the concept of “hero” was erased—making the summoning of unusual Servants possible. (c)