AD. 2017
The last era in which Magecraft still existed.

Society was created by human hands, but Mages grasped the truth of the world. Magecraft is comprised of techniques from past humans that cannot be explained by science, while science encompasses the techniques of future humans that Magecraft cannot achieve.

Researchers and scholars of both Magecraft and science have been gathered to maintain human civilization.

AD. 1950: Successful creation of the Phenomenon Recording Cyber Daemon: Laplace
AD. 1990: Completion of the Global Environment Model: Chaldeas
AD. 1999: Completion of the Near-Future Observation Lens: Shiva
AD. 2004: Completion of the Heroic Spirit Summoning System: Fate
AD. 2017: Completion of the Spiritron Calculation Engine: Trismegistus

The organization has continued to churn out splendid achievements, and thanks to Chaldea, the continued history of the human race was ensured up to 100 years in the future.

But then, in 2017...

Without warning, the future domain recorded by Shiva vanished.
Calculations identified proved the extinction of humanity in 2019.

Why? How? Who? By what means?
The researchers of Chaldea were perplexed by these questions.

Then, Shiva detected a new abnormality.
AD. 2004. A certain provincial town in Japan.
For the first time ever, a region that could not be observed appeared.

Assuming that this was the cause of humanity’s extinction, Chaldea carried out its sixth experiment, though it was still untested.
Time travel into the past.
A forbidden ceremony where they would convert Mages into Spiritrons and send them back in time. By intervening in events, they would locate, identify, and destroy the space-time Singularities.

They called the mission the Quest for the Holy Grail: Grand Order.

This is the title for those who would make a stand against human history, and battle fate in order to protect humanity.