After the 4th War for the Holy Grail ended in disaster, Kiritsugu tries to settle down in Fuyuki for working retirement... He's on a clock to live, but hopefully he can set Shirou on the right path, destroy the Holy Grail, and save Illya before he dies, right?
Right?!
The tropic paradise of Mataia Island is about to be plunged into hell, as a Holy Grail War on a scale the world has never seen before is set to break out.