The Daihasei Festival--a huge athletics festival attended by every school in Academy City, where the superpowered students attending these institutions gather to compete in a wide variety of competitions. And of course, Touma Kamijou is participating. His terrible luck is still in full effect--he's gnawed on by a famished Index, castigated by a representative of the festival management committee, and zapped mid-competition by none other than Mikoto Misaka. But Academy city's about to have a much bigger problem--and her name is Oriana Thomson.