The final battle against the Dark Territory drags on, as players from all over the world flood the Underworld's servers and plunge the Human Empire into utter chaos. Asuna Yuuki and her friends defend their new allies with everything they have, but their numbers are falling. Meanwhile, Alice Zuberg heads toward the World's End Altar while Gabriel Vecta Miller relentlessly pursues her. Meanwhile, members of Rath strategize a plan in an attempt to restore Kirito's damaged fluctlight. However, the intruders occupying the main control room have other plans. Surrounded by death and despair, when all hope seems to be lost, one voice reaches out to Kirito—a familiar one saying, I will always be by your side. Sword Art Online: Alicization - War of Underworld 2nd Season is the epic conclusion to Akihiko Kayaba's dream of creating artificial human intelligence. Now it is up to Kirito and his friends to protect this collapsing world from the people that still think it is just a game.

On her way to school one day, Suzume Iwato stumbles upon Souta Munakata, a young man searching for abandoned areas. The high school girl directs Souta to a nearby ruin, but out of pure curiosity, she herself decides to head to the same destination. Once there, Suzume discovers an isolated door with a dreamlike universe lying beyond it—a place that she can see and feel, but not enter. A strange stone rests on the ground nearby, but it turns into a cat-like creature and scurries away when Suzume lifts it. Suddenly afraid, she heads back toward her school, not realizing that her act of leaving the door open will have consequences. With the keystone released, the evil within the other universe can now freely escape and wreak havoc throughout Japan. Intending to correct her dangerous mistake, Suzume joins Souta—whose true goal is to prevent evil from festering—in finding and locking all open doors before the country is destroyed.

Clad in desert pink and the size of a mere child, the infamous Pink Devil mercilessly hunts down other players in the firearm-centered world of the virtual reality game Gun Gale Online. But in real life, this feared player killer is not quite who anyone would expect. A shy university student in Tokyo, Karen Kohiruimaki stands in stark contrast to her in-game avatar—in fact, she happens to stand above everyone else too, much to her dismay. Towering above all the people around her, Karen's insecurities over her height reach the point where she turns to the virtual world for an escape. Starting game after game in hopes of manifesting as a cute, short character, she finally obtains her ideal self in the world of Gun Gale Online. Overjoyed by her new persona, she pours her time into the game as LLENN, garnering her reputation as the legendary player killer. However, when one of LLENN's targets gets the best of her, she ends up meeting Pitohui, a skilled yet eccentric woman. Quickly becoming friends with Karen, Pitohui insists that LLENN participates in Squad Jam, a battle royale that pits teams against one another, fighting until only one remains. Thrust into the heated competition, LLENN must fight with all her wit and will if she hopes to shoot her way to the top.

The Soul Translator is a state-of-the-art full-dive interface which interacts with the user's Fluctlight—the technological equivalent of a human soul—and fundamentally differs from the orthodox method of sending signals to the brain. The private institute Rath aims to perfect their creation by enlisting the aid of Sword Art Online survivor Kazuto Kirigaya. He works there as a part-time employee to test the system's capabilities in the Underworld: the fantastical realm generated by the Soul Translator. As per the confidentiality contract, any memories created by the machine in the virtual world are wiped upon returning to the real world. Kazuto can only vaguely recall a single name, Alice, which provokes a sense of unease when mentioned in reality. When Kazuto escorts Asuna Yuuki home one evening, they chance upon a familiar foe. Kazuto is mortally wounded in the ensuing fight and loses consciousness. When he comes to, he discovers that he has made a full-dive into the Underworld with seemingly no way to escape. He sets off on a quest, seeking a way back to the physical world once again.