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.