The story takes place in an ordinary Japanese town, Fuyuki City. Hidden from society, there has been a deadly war going on in this town. Seven mages known as "Masters" summon powerful familiars called "Servants" and they all fight each other until the last one. The last one is said to attain the Holy Grail which will grant them a wish. Only a few know when this War started and what the Holy Grail is, but the war is about to begin again this year.

The main character is Emiya Shirou, who lost his parents in a fire and was adopted by a man who called himself a mage. Admiring his stepfather, he has been training himself to be a mage. However, he had no talent and he could barely use one type of magecraft. His stepfather has already passed away, and today he is a mage without any skills or knowledge. He is involved in the Holy Grail War when he accidentally summons Saber, who is said to be the strongest Servant of all…