Ten years ago, in the catastrophe that almost destroyed the world, Shirou Emiya was saved by the magician Kiritsugu Emiya and became his adopted son. Ten years later, Shirou continued to practice magic every day to fulfill the promise he made with his late adoptive father - to become a "partner of justice". One day, Shirou was involved in a duel between magicians called the "Holy Grail War". The rule is that a magician and a "heroic spirit" form a contract. In the so-called "Holy Grail War", the winner can obtain the Holy Grail to fulfill any wish. So, seven magicians and seven "heroic spirits" joined this fight to create miracles. Shirou Emiya knew that the catastrophe ten years ago was caused by the "Holy Grail War". In order to prevent the tragedy from happening again, he and his "heroic spirit" Sabar threw themselves into this "Holy Grail War" full of dangers and hardships.