The second season of the Japanese animated television series A Certain Scientific Railgun, based on the manga of the same name, follows Mikoto Misaka in her attempt to stop the deadly project that involves her clones and the most powerful esper in Academy City named Accelerator, with unlikely help from Toma Kamijo. The season, known as A Certain Scientific Railgun S, was produced by J.C.Staff and directed by Tatsuyuki Nagai with series composition supervised by Seishi Minakami.