Ten years after Kiritsugu Emiya summoned a Servant that should have been out of reach, the First Hassan-i-Sabbah, the original Old Man of the Mountain, the Fifth Holy Grail War has begun. Shirou Emiya, Master to an Assassin whose very existence threatens to tear him apart, must finish what his father began- and the First Hassan is not the only impossibility that stalks Fuyuki City.

He was an anomaly not meant to be in this world, yet fate would deem otherwise. After all, the fate of the world just may hang in the balance.