Koichi Haimawari is an ordinary and introverted college student who once had the dream of becoming a hero, but gradually chose to give up under the suppression of reality.In this era when superpowers are called "Quirk", although 80% of the world's population has some extraordinary power, there are very few people who are truly selected, become heroes and protect others.The gears of fate quietly rotate in an accident - when Koichi and Pop/Step are in danger, a mysterious vigilante Knuckleduster stepped forward, not only saving them, but also ignited the long-lost fire of hope in Koichi's heart.Then, they were unexpectedly recruited as members of the vigilante police and embarked on this path of justice full of unknowns and challenges.