The year is 1999. After the disaster of the Fourth Grail War, the Fuyuki Grail War was ended for good. Yet with the Einzbern too stubborn to give up 'their' prize, another was fashioned in the same manner: a homunculus to act as the core, a Grail to summon the Servants. However, it was imperfect; with only Justeaze's memories and not Justeaze herself, no contributions by a Magician, and Zouken being several hundred years older and a madman, full success was impossible. Instead, they made a one-off war on a tropical island, where the class system and numbers might not hold exactly.

At least one good thing comes of it: All the Evils of the World can't ruin [i]this[/i] fight.