After the Level Upper incident, life in Academy City seems to settle back to normal, until Misaka Mikoto, the Level 5 Electromaster known as Railgun, starts to sense that someone is watching her. The sensation is like the electricity in her body running backwards. She learns of an urban legend called Someone's Watching and discovers that other students have felt the same thing, some of them withdrawing from others entirely. As the unsettling episodes grow more frequent and Misaka becomes increasingly paranoid, her friends Shirai Kuroko, Uiharu Kazari and Saten Ruiko step in to help her face the unknown enemy. A single-episode action, fantasy and sci-fi OVA set in the Railgun corner of the Index universe.