Fantasy and reality collide when a surprisingly diverse group of online video-game addicts struggle to balance the game with personal relationships.
桐人 是使用NerveGear遊玩VRMMORPG「Sword Art Online」的玩家之一，很幸運的參與過封閉測試Beta Test和成功買下了正式版。在正式營運當天（2022年11月6日），包括桐人在內的約一萬名玩家就馬上「完全潛行Full Dive」進入正式版的SAO，享受著虛擬世界的樂趣。然而，四小時多後部分玩家們發現登出的指令消失了，認為只是系統暫時出錯的桐人以及開始陷入混亂的所有玩家都被傳送到起始城鎮的大廣場，但空中傳來的不是衆人等待許久的故障公告，而是自稱是SAO遊戲設計者「茅場晶彥」的人淡淡開始的死亡遊戲說明：不能登出是遊戲的正常現象，只有打倒位於「艾恩葛朗特頂樓第100層的最終頭目」——達成完全攻略——才是離開這個世界唯一的方法。並且，在遊戲內死去或是在强行現實世界中脫下NerveGear，玩家在現實世界中的腦部會被NerveGear所發出的高頻率微波破壞而死亡。
.hack follows several young players as they navigate the vast, mysterious MMORPG known as “The World” – a place, it turns out, that is sometimes impossible to leave.
Moriko Morioka is a 30-year-old single NEET woman. After dropping out from reality, she has taken off in search for a fulfilling life and ended up in a net game or "netoge." In the netoge world, she began her new life as a refreshing and handsome character named Hayashi. While starting out as a beginner, a pretty character named Lily reached out to help her. Meanwhile, in the real world, awaits a shocking encounter with a good-looking elite company employee, a mysterious blue-eyed blonde.
在高達模型的世界誕生了嶄新的網路服務，位於元宇宙空間內的用戶能透過操控虛擬化身，與其他用戶交流、進行線上高達模型對戰以及購買高達模型。
開始接觸這個新世界的北條利央在現實世界從烏露捷琪・西利亞那裡學習高達模型對戰的技術，而面具女士則在元宇宙世界教會他高達模型對戰的訣竅，利央藉此日益精進著自己的能力。
完成自己原創高達模型「太陽高達」的利央後來在元宇宙世界遇見——曾經參與高達模型對戰的強者們。
高達模型對戰Online（Gunpla Battle Nexus Online，簡稱GBN）」是能在電腦虛擬空間内使用高達模型執行各種任務，享受樂趣的最新網絡遊戲。初中生三上陸與死黨日高幸男，拉著同班同學矢代桃華，一起潛入那片廣大的世界。
他們成為GBN内的居民「潛行者」後，認識了對高達模型有著不可思議感應力的神祕少女莎拉，並開始與她一起行動…。在這個次元世界裡存在著小陸的偶像，冠軍「九條響也」等知名潛行者，憑著團隊系統可讓多名潛行者組成「部隊」，也有一群使用非法工具-「外掛貼紙」的「潛行聯黨」阻礙著他們的歷險。小陸等人透過不斷的相遇與經歷，除了高達模型以外，也開始一點一滴地創建自己的冒險故事！
Akira Oono is an ordinary working adult who manages the MMORPG Infinity Game. Fifteen years after creating the game, Oono decides to shut the servers down once and for all. However, as the clock strikes midnight, he somehow finds himself in the body of middle-aged Hakuto Kunai, Infinity Game's Demon Lord!
Soon after his mysterious transportation, he witnesses the demon Greole chasing after a little girl named Aku. Although he effortlessly dispatches the creature, Hakuto is still concerned; after all, he does not remember creating the girl or the demon! Doubting whether he truly is in the world of his creation, Hakuto decides to investigate. Bringing Aku along as his guide and companion, Hakuto sets out on a journey to find out exactly who or what summoned him to this fantasy world—all while leaving chaos and destruction in his wake.
Thousands of years ago, the 5 Kings guarded the land of the Xia Dynasty with magic artifacts. Later, the leader of the Dragon Clan, Zu Long, helped humanity by establishing the Yun Chui Empire. The empire overlooks the calm ocean where Xi and the Black Water Clan have maintained it for 1,000 years in peace. Now, waves are surging from below and chaos will rise once again.