The Fifth Holy Grail War taking place in Fuyuki City has reached a critical point. The lives of all participants are now in danger as the hidden enemy reveals itself. Shirou Emiya, Rin Toosaka, and Illyasviel von Einzbern uncover the corruptive nature of the shadow that has been spreading throughout the city. The situation is dire, and they must defend their loved ones against a seemingly insurmountable enemy force, even if some of those foes were once friends, or more. The final act of this frantic battle is about to commence, and Shirou's ideals will be put to the test. An agonizing dilemma emerges: is it possible to salvage a world where everything seems to have gone wrong?