They always shared the same moments. They thought it would be like this for eternity. ――― Kirito awakens in a completely unknown virtual world, but something about it feels a bit familiar... Set in Underworld, an expansive world introduced in the SWORD ART ONLINE anime, Kirito sets out on adventure in the series' latest RPG! Enjoy seamless, action-packed real-time battles using a combination of sword skills, sacred arts, and your favorite SAO characters! Kirito meets a boy named Eugeo. Somewhere deep within their hearts is a lingering promise. To fulfill that promise and avoid losing each other, they set out on adventure together. Nothing will keep them from reaching their goal.