Shirou Emiya lost his parents when he was young and was adopted by sorcerer Kiritsugu Emiya. Although he yearns to become an ally of justice, Shirou has limited powers and was unable to become a strong sorcerer like his father. One day he was drawn into the Holy Grail War and had to summon a female "Servant" known as Saber in order to protect himself. It turns out that the Holy Grail War involves a series of battles among powerful sorcerers to fight for the possession of a relic that will grant one's wishes, the Holy Grail. There are altogether seven "Masters" who can summon their respective "Servants" from different classes. These "Servants" have to hide their names in order not to reveal their weaknesses to the enemies.