Just when the Holy Grail was about to be cut off, the eighth heroic spirit, Amakusa Shiro, was summoned from it. His method of seeking an ideal world was different from that of Emiya and was denied by Emiya. In order to "save" this world, Amakusa used the Holy Grail to create a new but hypocritical world. This world became a so-called singularity-like existence. It was detected by Chaldea, and Fujimaru Ritsuka was summoned here...