The year 2015 CE. The last era in which magecraft still thrived. The Chaldea Security Organization was founded to focus on preserving the continuation of human history. They observe a world which magecraft couldn't observe and science couldn't measure all to prevent the certain extinction of humanity. But one day, the future that Chaldea continued to observe disappears and humanity's extinction in 2017 becomes clear. Rather, it had already happened. The cause seems to be related to Fuyuki, a provincial town in Japan, in the year 2004 CE. There, an "unobservable region" that had not existed before appears. Based on the assumption that Fuyuki is the reason for humanity's extinction, Chaldea issues an order to explore, investigate, and possibly destroy this singularity – a quest for the Holy Grail, the Grand Order.

After battling their way through all seven Singularities, the Chaldea Security Organization has finally arrived at the endpoint of the Grand Order: The Final Singularity, Grand Temple of Time: Solomon. Now is the time to defeat the root of all evil, Solomon, the King of Mages. Now is the time to reclaim the future. With the final operation looming large, Romani Archaman considers the choices he will soon have to make, Mash Kyrielight dwells on life's limitations, and Fujimaru prepares to receive a new Mystic Code. All their many encounters have led to this moment as Fujimaru and Mash at last embark on their final operation...