In the uninhabited Mirror World, indistinguishable from reality, where even the presence of people, the sound of cars, and the rustle of the wind have vanished. At its center, in the void, the all-powerful wish-granting device, the Philosopher's Stone, awakened for the first time in a hundred years, floats quietly, filled with a deep, soft ruby light. No one has ever made its power their own.

- A professional sniper loads bullets into his rifle and firmly shakes hands with the precious person beside him. - A young girl with white hair, carrying her family's ancestral wish, issues orders for victory to her attendants. - A martial arts master cracks his knuckles, a smile etched on his lips as he waits for the time of battle. - And hundreds of other pairs of Masters and Familiars were readying themselves, each with their own intentions.