Shinji Satoh

Class 1-A visits Nabu Island where they finally get to do some real hero work. The place is so peaceful that it's more like a vacation... until they're attacked by a villain with an unfathomable Quirk! His power is eerily familiar, and it looks like Shigaraki had a hand in the plan. But with All Might retired and citizens' lives on the line, there's no time for questions. Deku and his friends are the next generation of heroes, and they're the island's only hope.

The time is UC 1926. The Imperial Army's 203rd Air Mage Battalion led by Major Tanya Degurechaff has won the battle to the south against the Republic's stragglers. They expected to be given a vacation after returning victorious, but instead receive special orders from Staff HQ as soon as they get home. They are told that there were signs of a large-scale deployment near the Empire-Federation border. Faced with the prospect of a new major enemy, the desperate Empire fans the flame of war. Meanwhile, an international volunteer army spearheaded by the Commonwealth set foot in Federation territory. As they say, the enemy of an enemy is your friend. They suffer through misfortune purely out of national interest, and among them is a young girl. She is Warrant Officer Mary Sue, and she takes up arms hoping to bring the Empire, who killed her father, to justice.

All Might and Deku accept an invitation to go abroad to a floating and mobile manmade city, called 'I-Island', where they research quirks as well as hero supplemental items at the special 'I-Expo' convention that is currently being held on the island. During that time, suddenly, despite an iron wall of security surrounding the island, the system is breached by a villain, and the only ones able to stop him are the students of Class 1-A.

Sixteen years ago, a mysterious masked ninja unleashes a powerful creature known as the Nine-Tailed Demon Fox on the Hidden Leaf Village Konoha, killing many people. In response, the Fourth Hokage Minato Namikaze and his wife Kushina Uzumaki, the Demon Fox's living prison or Jinchūriki, manage to seal the creature inside their newborn son Naruto Uzumaki. With the Tailed Beast sealed, things continued as normal. However, in the present day, peace ended when a group of ninja called the Akatsuki attack Konoha under the guidance of Tobi, the mysterious masked man behind Fox's rampage years ago who intends on executing his plan to rule the world by shrouding it in illusions.