Eight years ago in Germany, Kiritsugu Emiya and his wife, Irisviel von Einzbern, welcome the birth of their daughter, Illyasviel. Though Kiritsugu fears he will lead Irisviel to her death with the upcoming Fourth Holy Grail War, Iris assures him that he is a good man who will end his torment and fulfill their ideals. Three years ago, the priest Kirei Kotomine learns that he has been chosen as a participant for the Holy Grail War; his father Risei, the war's moderator on behalf of the Catholic Church, and Tokiomi Tosaka arrange for Kirei to become Tokiomi's pupil in magecraft in order to give Tokiomi an advantage and help Kirei get over the death of his wife. One year ago in Fuyuki City, Kariya Matō visits his childhood friend Aoi Tōsaka and her daughters, Rin and Sakura, but he is shocked to learn Sakura has been adopted by the Matō family as the Matōs want a heir that uses magic and is horrified to discover on what has been done to her. Confronting his father, Zōken, Kariya strikes a deal to become a mage in the upcoming war and win the grail in order to free Sakura and return her to her mother and sister. In the present, at the London Clock Tower, Kayneth Archibald El-Melloi dismisses and humiliates a thesis by one of his students, Waver Velvet, who theorizes anyone can be great mage by hard work and practice other than by their bloodline. Angered by the humiliation, Waver decides to prove his teacher wrong by also joining the Grail War by stealing Kayneth's artifact needed to summon a Servant and heads to Fuyuki City. As Kirei and Kiritsugu learn of each other's skills, they are disturbed by how they cannot know what the other man's goals for the war are. After receiving the scabbard of Excalibur, Iris is now hopeful that they can now summon King Arthur of the Saber class but Kiritsugu worries that Arthur's chivalry will clash with his pragmatic methods. As Kiritsugu, Tokiomi, Kariya and Waver summoned their servants, Kiritsugu and Iris are stunned to see the summoned King Arthur is actually a girl.