In 2022, the genius programmer Akihiko Kayaba developed the world's first full-dive equipment "NERvGear". This revolutionary machine brought infinite possibilities to the VR (virtual reality) world. Four years have passed since then. . . . . In order to compete with "AmuSphere" (the second-generation civilian full-dive machine), the successor VR machine of "NERvGear" released a next-generation wearable device "Augma" that replaced the full-dive function and is a state-of-the-art model that maximized the AR (augmented reality) function. Since "Augma" can be used safely and conveniently even in the awakened state, it spread among players in an instant. This killer content is called "Ordinal Scale (OS)", an ARMMORPG dedicated to "Augma". Asuna and her friends will play this game, and Kirito is also ready to join the battle... . . .