In Snowfield, a distant city in the western U.S., a peculiar event called the 'false Holy Grail War' transpires, distinct from its Fuyuki counterpart. Vigilant individuals have been monitoring the Holy Grail's signs in Snowfield, which the Mage's Association discovers to be a flawed imitation of the Fuyuki system. This flawed replica omits a class and summons unconventional Servants, creating a truly peculiar scenario. Meanwhile, a mysterious faction within the U.S. government sets its schemes in motion, prompting the successive summoning of Servants...