Seeking the power of the Holy Grail, something that can make miracles occur, seven different mages summon seven Heroes, and fight until the last man remains--a battle of epic proportions, the Holy Grail War. In preparation for the war, various participants are chosen from all over the globe. Eight years ago in Einzbern Castle in Germany, a girl named Illyasviel is born. Her father, Kiritsugu Emiya, embraces her knowing he will be part of the battle, as well.

Battle rages throughout Einzbern Castle: Kayneth's magical mercury sphere versus Kiritsugu's formidable gun arsenal, Saber and Lancer join forces against Caster in the forest, and Irisviel detects a new enemy as she and Maiya make their escape.

Kiritsugu and company are wrapping up after the assault on their castle, and the Einzbern Master decides to ignore Saber's desire to pursue Caster, instead leaving on his own to finish off Kayneth. But Kayneth, after being saved by Lancer, has awakened to find himself bandaged and strapped to a bed. Sola-Ui explains the hopelessness of his current situation, and offers a shocking proposal...

Natalia has raised Kiritsugu since rescuing him from the island. He has followed her in every step in becoming an assassin. Over the years their relationship has grown to the point of mother and child, so what Kiritsugu does next is…