Sword Art Online is an anime based on a series of light novels which has just hit the midway point of its TV run. Twelve episodes in, it is the smartest anime I have seen in years—even including the recent Lupin III. But before we get into why this is the case, let's take a look at the story.
When the first 10,000 lucky people log into Sword Art Online, a new, highly anticipated virtual reality MMORPG, they find themselves trapped in the game with no way to log off. Worse yet, the players discover that if they die in the game or the connection is severed from the outside, the VR helmet will microwave their brains and kill them in the real world. The only way out is to pass all one-hundred floors—each a self-contained world in and of itself—and defeat the game's final boss.