|Spoiler Alert: This article or section contains details about plotlines not covered in the anime. Do not proceed unless you wish to be spoiled. |
Nearly three months since the Ocean Turtle was raided by Gabriel Miller's forces, leading to Alice being revealed to the public, and nearly two months since Kirigaya Kazuto (Kirito) awoke from his comatose state after experiencing two hundred years worth of time in Underworld, September 27, 2026 started as just an ordinary Sunday for the boy. While Lisbeth, Silica, and Yui were busy levelling their skills against monsters on the 45th Floor of New Aincrad in ALfheim Online, Kirito decided to finish his homework at their log house before joining the girls. However, soon after the boy was joined by Alice and Asuna, a mysterious phenomenon engulfs the game at exactly 17:05: earthquakes rock the entire world as the sky is covered in "Warning" and "System Announcement" signs just like on the fated day when Sword Art Online became a death game. This phenomenon marked the moment when all the games on The Seed Nexus were abruptly and forcefully merged into one: a Survival Massively Multiplayer Online game known as Unital Ring.
With New Aincrad crashing down onto this new world, Alice, Asuna, and Kirito managed to save the log house from being destroyed by softening its landing. However, the three of them now found themselves in an unknown forest with only their equipped items, two of their greatest weapons, one most-developed skill from ALfheim Online... and level 1 accounts. The only clue the players were given as to the goal of this new game is a cryptic announcement by the disembodied voice of a young girl, urging them to visit the land marked by an aurora, where the first player to reach it would be granted everything. Although the players are allowed to log out of Unital Ring of their own accord, unlike in the death game, their avatars remain vulnerable in the world even when the player is not online, while any player who loses their life in-game may never log back into Unital Ring again.
In order to uncover the mysteries of this new game, Kirito's group will have to deduce the mechanics of this new world to save their crumbling log house and upgrade it into a stronghold that could withstand attacks from malicious players, reunite with his friends scattered across the map, and recruit the inhabitants of this new world to join their cause. However, their rise to power draws the ire of a certain malicious individual, who desires to dominate the players in order to achieve her goals. Meanwhile, Kazuto learns from Kikuoka Seijirou that someone has managed to gain access to Underworld. In order to discover who this intruder is and what they are plotting, the boy will need to dive into Underworld with Alice and Asuna once more. There, Kirito will encounter a man with a striking resemblance to his fallen partner and best friend...