Within Academy City, espers are ranked from powerless 'Level 0' to the formidable 'Level 5,' with only seven achieving the highest rank. Among them is Accelerator, the focus of Toaru Kagaku no Accelerator, who sacrifices his strength to safeguard Last Order. After a period of recovery, his quiet life takes a turn when he saves Estelle Rosenthal, a girl linked to Last Order. This self-imposed tranquility shatters as Accelerator is entangled in a perilous scheme by a malevolent group, Disciplinary Action, aiming to exploit Last Order. With this dangerous plot unfolding and the young girl in jeopardy, the burden falls on the most potent esper and his new ally to shield Last Order and defend Academy City from impending threats.