I've been watching only a handful of shows in the new season and three of them (Kannagi, Tora Dora and To Aru Majutsu no Index) started off pretty same-ish but in the next episode, distinctions were made and I made a startling discovery; To Aru Majutsu no Index is about as close to an Mx0 anime as the world is going to get. I liked it the best of the three school life shows but the second episode cemented it, this is going to be a good if not great anime.
The basic story can only really be told through the setting. In an alternate world Tokyo, there is a district that exists solely for students ("Student City") and the day to day maintenance of the entire place is automated by machines. Beneath the surface of this ideal academic world is a secret; many of the students are Espers (people who can use psychic power) which sometimes drives people into conflict.
Our main character Toma Kamijo is a well meaning but laid back Esper who happens to have almost no power at all, he's at the absolute bottom rung of the Esper society. His only ability is in his right hand, which allows him to cancel the powers of other Espers. In order to win fights (or often just get away, since he has little taste for battle) he has to use his initiative or cunning to defeat his opponents.
One day, a young woman appears on Toma's balcony just as he's about to leave for school. This woman, who calls herself Index, claims bad people are after her because she holds 103,000 grimoires that contain ancient knowledge of magic. Toma doesn't believe in magic and thinks that Index is talking about Espers, but she insists magic is REAL and appears to not believe in Espers. Toma tries to prove his point that magic = ESP by touching Index's "walking church" nun outfit with his right hand, since it allegedly has great magic power. It promptly explodes, but is seemingly repaired later by Index.
After returning late from school, Toma discovers Index at his doorstep, unconscious and bleeding heavily. She had forgotten her cap in Toma's house and decided to stop by to pick it up. As Toma cradles the near lifeless Index, a man in black then walks up to him and introduces himself as a magician seeking the library of 103,000 grimoires.
Anyway, while this anime isn't exactly like Mx0 it carries on many of the themes, particularly in Toma. As a light novel adaption I can feel that the series will take on a mature tone even beyond what was seen in Mx0 - I have high expectations and feel this is one of the best shows of the season!