The war is over, the villains are either arrested or sent to rehabilitation depending on what they've done and their mental state. Shigaraki was sent to UA for rehabilitation, dabi was sent to Tartarus for around 7 years time to be rehabilitated so he can be a functional member of society. Spinner was in Tartarus, toga was in UA to be rehabilitated. it was chaos at first, the city had to be rebuilt and so on. that took years. class 1-A became pro heroes and had kids.

Karo Todoroki: tsuyu and shotos kid. Azi Bakugo: Bakugo and Denkis kid. Shimi Jiro: Shinso and Jiros kid. Hitoro Yayarozu: Momo and Tokoyamis kid. Kenji Shoji: Koda and Shoji's kid. Akio Sero: Mina and Seros kid.

the new class 1-A Shimi, Kenji, Hitoro, Azi, Karo, Akio and more are in class, Aizawa is trying to get them to calm down. its not working out so well. When they quiet down they look at Aizawa, expecting some grand speech or something. but all they get told is "get gym uniforms on and meet me in the USJ" which was odd, most teachers give a speech about how they're gonna become heroes and sum shit like that, apparently not Aizawa. that's fine though.