The Humane Continuity Guarantee Agency, Chaldea, observes a world that can not be seen only with magic. One day, the near future observation lens Shiva will incinerate the future of humanity in 2017-it has been proven that humanity will be extinct. "Unobservable areas" suddenly appearing in various places in history-singularities. Chaldea assumes this is the cause of human extinction and decides to travel in time to the past. Members of Chaldea, such as Tatsuka Fujimaru, Mash Kyrielight, Leonardo da Vinci, Romani Archiman, intervene in singularity events, A forbidden ritual to elucidate or destroy this-the name is being searched for “the Holy Grail (Grand Order)”. The wise king Gilgamesh dismantled Babylon and rebuilt it as a fortress city, Babylonia, to stop the onslaught of evil beasts. Gods, beasts, and humans. The battle for the survival of the species has now begun.
2015. The last era when magic was still established. The Humane Continuity Guarantee Agency, Caldea, observes a world that can not be seen only with magic, a world that can not be measured only with science, and conducts research day and night to prevent the decisive extinction of humanity, with a preservation that preserves human history stronger than anything else Continued. One day, the future territory that had been continuing observations in Caldea disappeared, and calculations showed that humanity would be extinct in 2017-or no, it was proved. Meanwhile, "unobservable areas" suddenly appear in various places in history. Chaldea assumes that this is the cause of human extinction, and issues a mission to search for and elucidate singularities, or to destroy, "Search for the Holy Grail" --- Grand Order. Tachika and Mash, who were assigned the duties, went to a singularity that was confirmed in 1273. The singularity itself was becoming a "history that should not exist."