Touma Kamijou is a student living in Academy City, a highly advanced place in terms of technology. Despite being gauged as a level zero esper (no powers), he possesses on his right hand the Imagine Breaker, an ability that negates any power whatsoever. Touma finds a young girl named Index who is trying to run away from Necessarius, a powerful magic organization that she is member of. Blessed with the skill of memorizing any sort of information, she holds 103,000 forbidden magical books within her head. As science and magic cross paths, Touma must face several dangers amid espers and magicians who appear in the exciting scientific town.

Misaka's electro-manipulation skills - and her delightfully destructive railgun projectile movement - make her a rock star in Academy City. The techno-metropolis is filled with supernaturally powerful students known as Espers, including Misaka's flirtatious friend and roommate, Shirai Kuroko. She uses her teleportation skills as a member of the Judgment law enforcement team, fighting crime alongside fellow agent Uiharu. Joined by their friend Saten, a spunky Level 0 Esper, Misaka, Kuroko, and Uiharu have a blast taking on danger whenever and wherever it arises.