You thought you were an ordinary high school student. You, your classmates, and your teachers all went about their very familiar, very predictable routines, week after week.

Then, quite by accident, you discovered the truth: Your “school” was part of a virtual world, the chosen battleground for the so-called Moon's Holy Grail War. Most of your friends and teachers were NPCs, slaves to the system, created for the sole purpose of facilitating the “game,” then deleted at the game's conclusion. For all you knew, you were one of them, an NPC yourself. But through a twist of fate, you were also one of the players, 128 of them in all, each forced to choose a Servant and fight in a single-elimination tournament - to the death.

Then you won. And the Moon Cell, recognizing you as both the winner and an NPC, granted you a wish even as it began to delete you. You made your wish on behalf of all the NPCs on SE.RA.PH, granting them the freedom to live their own lives as they saw fit. With the NPCs no longer bound to the rules of the game, the wish effectively ended the cycle of the Holy Grail War, leaving you alive as the sole remaining Master on SE.RA.PH.

Together with your Servant, a flamboyant female incarnation of Nero Claudius, you were crowned ruler of the digital domain. But other Servants, also freed from the rules, began choosing up sides, and a lawless war - made all the more lawless by a faction of alien destroyers from a faraway star - soon engulfed the new-made world.

With passion, perseverance, and a few clever gambles, you and your loyal Servants won through, uniting SE.RA.PH and its people under your banner. The virtual world is quiet now, and its citizens, NPC and human alike, live their lives in prosperous peace.

But in a world where any historical hero or villain can emerge from the ether at any moment, nothing stays quiet for long...