As the Daihasei Festival commences in Academy City, the renowned Tokiwadai Middle School enters the competition with the formidable 'Ace of Tokiwadai,' Mikoto Misaka leading the charge. While competitors strive against her unmatched power, a shadow looms over the festivities. With the city opened to the outside world, sinister factions scheme to exploit the chaos. As threats converge on Misaka, secrets hidden in the city's underbelly surface, revealing a darker side to Academy City. Toaru Kagaku no Railgun T delves into a world of terrorism and clandestine machinations, where danger lurks at every corner for Misaka and her allies.