Tsukimihara Academy may look peaceful, but in reality, it's a technological nightmare - a computer-generated high school serving as the arena for the upcoming Holy Grail War, which governs the fate of Earth's souls. To participate, 256 candidates with the weakest potential to become "Masters" are chosen, although only 128 are eventually selected to compete - each given a Servant - while the Academy disposes of the rest. After finding himself soaked in blood, Hakuno Kishinami is steadfast in overcoming his injuries. Driven by an inexplicable wrath, he resolves to fight until the end. One day, while exploring, he comes across a crimson sword plunged into the ground, and upon pulling it out, he summons Saber, his Servant, who employs a mesmerizing flurry of rose petals to eliminate Hakuno's foe. Empowered by his newfound powers, Hakuno sets his sights on the Angelica Cage, the Moon Cell's core, in order to unravel the dark secrets of his past and untangle the enigma of this false world.