In Academy City, Kuroko Shirai, a member of the Public Moral Committee, Judgment, goes to stop some thugs only to find her senior at Tokiwadai Middle School, Level 5 esper Mikoto Misaka, has already dispatched them, much to Kuroko's chagrin. Meanwhile, Kuroko's colleague in Judgment, Kazari Uiharu of Sakugawa Middle School, is invited by Kuroko to meet Mikoto, bringing along her friend and classmate, Ruiko Saten. As the group go to a créperie, Kazari and Ruiko are both surprised that Mikoto is nothing like the rich, snobby socialite image that they had in mind. Just then, a nearby bank robbery takes place, with Kuroko heading into action to stop the robbers, including a pyrokinesist, using her teleportation powers. When Ruiko gets hurt while rescuing a young boy from being kidnapped by the remaining robber, Mikoto becomes angered and uses her electromagnetic powers to fire her signature 'railgun' attack at him and stop his escape. With the robbers apprehended by the city's police, AntiSkill, Ruiko is thanked by everyone for her brave rescue.