In a conflict known as the Holy Grail War, Mages (referred to as Masters) and their Heroic Spirits (known as Servants) engage in a fierce battle to seize control of the Holy Grail, a legendary artifact capable of granting any wish.
After the conclusion of the Fifth Holy Grail War in Japan, several years have passed. However, ominous signs suggest that a new Holy Grail is about to materialize in the city of Snowfield, located in western America.
As anticipated, Masters and Servants begin to assemble, drawn by the beckoning of the Holy Grail. However, peculiarities arise, including the absence of a specific Servant class, inexplicable summonings of Servants, a nation veiled in secrecy, and the transformation of the city into a veritable battlefield.
Confronted with these aberrations, the Holy Grail War takes a twisted turn, descending into the depths of madness. Now, a captivating spectacle unfolds—a masquerade involving both ordinary humans and legendary heroes—unwittingly performing on the stage of a counterfeit Holy Grail.