Bored with life and considering the real world to be just a “crappy game,” savvy sibling shut-ins Sora and Shiro have withdrawn into their own fantasy world filled with video games. However, one day they find themselves summoned to another world by a boy who calls himself “God,” their abilities are about to be put to the ultimate test! Now not only their fates — but the fate of all of humanity — will be decided by a series of games that may just be the hardest these super-geniuses have ever faced!

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...

Jinta Yadomi and his group of childhood friends have become estranged after a tragic accident split them apart. Now in their high school years, a sudden surprise forces each of them to confront their guilt over what happened that day and come to terms with the ghosts of their past.

Emma, Norman and Ray are the brightest kids at the Grace Field House orphanage. And under the care of the woman they refer to as “Mom,” all the kids have enjoyed a comfortable life. Good food, clean clothes and the perfect environment to learn—what more could an orphan ask for? One day, though, Emma and Norman uncover the dark truth of the outside world they are forbidden from seeing.

Tomozaki is one of the best gamers in Japan, and in his opinion, the game of real life is one of the worst. No clear-cut rules for success, horribly balanced, and nothing makes sense. But then he meets a gamer who’s just as good as him, and she offers to teach him a few exploits…

Sorata Kanda, a high school sophomore living in Sakurasou, the den of their academy's problem children, spends his days being dragged around by the strange residents, swearing he's going to escape Sakurasou one day.