Misaka Mikoto, known as the Railgun, is one of the top level espers in Academy City. A City that is considered to be a highly developed place in terms of technology. It is said to be 20 to 30 years ahead of the rest of the world. She attends Tokiwadai along with her roommate Kuroko Shirai, another high level esper who is a member of Judgement, a law enforcing agency composed of students. Mikoto’s power gives her something of a celebrity status around town and Shirai’s partner in Judgment, Uihara Kazari is desperate to meet her. Uihara’s best friend Saten Ruiko suspects Mikoto’s elite status would make her stuck up, but after they meet her, they quickly hit it off and the four of them become close friends and embark on a series of adventures throughout Academy City.