Plot
In the futuristic Academy City, which is made up of 80% students, many of whom are espers possessing unique psychic powers, Mikoto Misaka is an electromaster who is the third strongest of a mere seven espers who have been given the rank of Level 5. The series focuses on the exploits of Mikoto and her friends; Kuroko Shirai, Kazari Uiharu, and Ruiko Saten, prior to and during the events of A Certain Magical Index.