Battling to comprehend his fractured memories, high school student Hakuno Kishinami reaches school with a sharp headache. Gazing out the window of his classroom, he spots two girls in the courtyard starting to fight. The impact of their clash breaks the windows, yet, surprisingly, the students remain unfazed. A man clad in armor enters, slaughtering the students with his lance and forcing Hakuno to flee for his life. After escaping the frenzied knight, Hakuno realizes he has become completely amnesiac, recalling only the phrase "Holy Grail War." Wandering through the deserted school, he stumbles through the building until he is attacked by two strangers. Bleeding out and surrounded by corpses, he clings to life with no sense of self. As the pair of men move to finish off the dying Hakuno, a voice calls to him. Snapping him back to reality, a woman in a vibrant red dress tells him that his end has not yet come. Identifying him as her Master, she draws her blade against the assailants, affirming a contract between the two that will carry Hakuno through the coming trials and tribulations.