The world is set in a school called Tsukumihara Academy, a fictional place existing with an artificial environment called the Moon Cell. There, the Moon Cell orchestrates a replication of the Holy Grail War using a system called Serial Phantasm or SE.RA.PH, which handles the summoning of Servants. Each of the 128 participants in the war must duel the other Masters in a place called the Arena, where failure results in deletion from the digital world and death in the other. When only one remains, the "Holy Grail" shall grant the victor's wish.