The year is 2016, and glitches found in humanity's past threaten the sustainability of its future. The Chaldea Security Organization—tasked with preserving human history for as long and as strongly as possible—has developed a new method of time travel to repair these events, stabilizing humanity's future. But when an unknown threat pushes mankind to the brink of extinction, young recruits Mash Kyrielight and Ritsuka Fujimaru find themselves at the helm of the rescue mission: Obtain the Holy Grail in a face off against fate itself...