Amane lives alone in an apartment, and the most beautiful girl in school, Mahiru, lives just next door. They've almost never spoken—until the day he sees her in distress on a rainy day and lends her his umbrella. To return the favour, she offers him help around the house, and a relationship slowly begins to blossom as the distance between them closes…

Considered a genius due to having the highest grades in the country, Miyuki Shirogane leads the prestigious Shuchiin Academy's student council as its president, working alongside the beautiful and wealthy vice president Kaguya Shinomiya. The two are often regarded as the perfect couple by students despite them not being in any sort of romantic relationship.

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...