The To Aru Kagaku no Railgun side story is based on Kamachi's original story set in Academy City, a city where about 80% of its 230,000 citizens are students. The story deals with the adventures of Misaka Mikoto, one of the Level 5 psychics in the To Aru Majutsu no Index light novels
This show is very funny and entertianing but is has some nudity so i say be at least 13-14 years old before you watch this. the animation is pretty good and storyline is ok but the way the characters are extremely funny trust me You won't be disapointed even if you don't trust try it.
There is only one thing I hate about this anime that there is only 24 episodes.