Touma Kamijou finds no respite. Following Academy City"s incursion, diplomatic strain escalates as the scientific and sorcerous camps clash directly. Rumors spread that Academy City plans to wage war on the Roman Catholic Church, which would ignite worldwide conflict. Touma is quickly thrust back onto the battlefield, determined to shield his comrades and allies and friends, as the world teeters on the brink.
Toaru Majutsu no Index III marks the concluding chapter of the original saga, where Touma, Accelerator, and the authentic Level 0 Shiage Hamazura pursue distinct paths toward the climax of the initial light‑novel narrative their destinies intertwine in a final, decisive showdown.