慶安四年、江戸。
血で血を洗った乱世の終結から早数十年、
民は泰平を享受する日々を送っていた。

だが、その裏で人知れずして七人七騎の殺し合い、
“盈月の儀（えいげつのぎ）”が幕を開ける。

浅草に住まう青年、
宮本伊織を渦中へと巻き込みながら―――

The 4th year of the Keian Era, Edo Period.
It has been several decades since the end of a turbulent, blood-soaked era.
People were enjoying peace and tranquility.
But, a battle between seven pairs of Masters and Servants is about to begin,
as the "Waxing Moon Ritual" unfolds in the shadows.
Miyamoto Iori, a young man in Asakusa, finds himself caught in the violence of a Holy Grail War.