The Grand Orders, singularities on history from unknown origin started to form generating the possible destruction of humanity in the near future, Chaldea the organization that watches over the future of humanity prepared theyselfs to stop those singularities, they assembled the a group of potential masters to use the beings called servants to fight inside those singularities and save history, a normal human with potential to be a master was called for such job, a innocent girl who worked at Chaldea was called to support those masters, and yet, someone was called to watch over the plans to save humanity, yet none of them knew the truth behind the events about to happen.
You, Y/n, are the final Master of Chaldea. Everything is going according to plan until you begin to hear a voice calling from the darkness. Soon, you find yourself trapped in the dreaded Château d'If, with only a stranger as a guide. He was strictly off limits. Reserved, cold, maybe a little chaotic...and yet, you can't help but start to care for him.