In the near future, a Virtual Reality Massive Multiplayer Online Role-Playing Game (VRMMORPG) called Sword Art Online has been released where players control their avatars with their bodies using a piece of technology called Nerve Gear. One day, players discover they cannot log out, as the game creator is holding them captive unless they reach the 100th floor of the game's tower and defeat the final boss. However, if they die in the game, they die in real life. Their struggle for survival starts now...

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. Pitohui insists that LLENN participates in Squad Jam, a battle royale. Thrust into the heated competition, LLENN must fight with all her wit and will if she hopes to shoot her way to the top.

When the creator of a popular video game system dies, a virtual contest is created to compete for his fortune.

It explores the concept of simulated reality through a narrative journey, beginning with a lullaby that embodies blissful ignorance - subtly disrupted by audio-visual ‘glitches’ hinting at a deeper truth.

One day, while playing the online game Elder Tales, 30,000 players suddenly find themselves trapped in another world. There, eight-year veteran gamer Shiroe also gets left behind. The trapped players are still alive, but they remain in combat with the monsters. The players don't understand what has happened to them, and they flee to Akiba, the largest city in Tokyo, where they are thrown into chaos. Once proud of his loner lifestyle, Shiroe forms a guild called Log Horizon with his old friend Naotsugu, female assassin Akatsuki and others.