In order to obtain the miraculous art of the "Holy Grail" that can fulfill all wishes, seven magicians summon seven heroic spirits to launch a holy war. They must fight to the end, because in the end only one person can obtain the power of the "Holy Grail" - the "Holy Grail War" begins. This holy war has not been calmed down by the past three battles; now, the fourth battle is about to begin. With the determination to win, the magicians gathered at the battlefield called "Fuyuki" to welcome this sacred battle. However, one of them does not understand why he is fighting. He is Kotomine Kirei. Kotomine Kirei cannot understand why he was chosen and given the Command Seal. However, fate will lead him to meet another participant, that is Emiya Kiritsugu. Emiya Kiritsugu desires the "Holy Grail" more than anyone else. In order to achieve his goal, he uses all cruel means. In the popular game "Fate Stays Night", the fourth battle 10 years ago is only briefly mentioned. The truth about Shirou's adoptive father, Rin's father, and the young and energetic Kotomine Kirei's going to the war will now be revealed one by one...