The student-filled Academy City is at the forefront of scientific advancement and home to the esper development program. The seven "Level 5" espers are the most powerful in Academy City, and ranked third among them is middle schooler Mikoto Misaka, an electricity manipulator known as "The Railgun." When strange incidents begin occurring throughout the city, she finds each crime to be connected to the elusive "Level Upper," a legendary device that allegedly increases the esper level of its user. As the situation escalates, it becomes apparent that there is more to the Level Upper than meets the eye, and that Academy City may be a far more twisted place than the glamorous utopia it appears to be. Toaru Kagaku no Railgun focuses on Mikoto and her friends—and the dangerous situations they find themselves in—as they get caught up in the matter of the Level Upper. As Mikoto says, "There's never a dull moment in this city."

Mikoto Misaka and her friends are back, investigating rumors across Academy City. Soon, Mikoto discovers something terrifying: horrific experiments are taking place throughout the city, involving the murder of thousands of espers. Moreover, these espers are far from just ordinary people: they are clones of Mikoto herself. Feeling responsible for their treatment, she sets off to put an end to the experiments; however, the forces opposing her are much more dangerous than she anticipated, and Mikoto finds herself up against some of the most powerful espers imaginable. Toaru Kagaku no Railgun S continues the story of the Railgun as she desperately fights to put an end to the inhuman experiments that she believes she helped cause, her life dragged deep into despair in the process. There's never a dull moment in Academy City, but no one ever said all of them would be pleasant. [Written by MAL Rewrite]

Episodes 4-6 of the Soukyuu no Fafner: Dead Aggressor - The Beyond series.