After bringing an end to World War III, Touma Kamijou disappears from the world. Both sides-magic and science-take the time to rest and regroup. While Accelerator spends his days with Last Order and Misaka Worst, Shiage Hamazura uses the secrets he gained in Russia as a bargaining chip and returns to Academy City to reform Team ITEM. It seems like peace is here at last. That is, until a new group called the Freshmen arrive...?