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.
12-year-old Oriko Seki, who lost her parents in a car accident, ended up living in her grandmother's Onsen Ryokan "Haru no Ya." With the ghost "Uribou" cohabitating with her and all the other odds, she ended up training to be a young female innkeeper. At first, she didn't like the training, but gradually felt her admiration for her title and began to train seriously. Thus, the growth of the young warrior Oriko begins.
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.
