Eri made a mistake in training and turned Aizawa into a teenager. Aizawa doesn't remember a tthin about the last 16 years of his life and have to retake UA high or somehow reverse it. He only remember his old childhood friends Present Mic that's now a teacher and Kurugiri that's now a villain. Aizawa is with Class 1A talking with the students, only Bakugo and Deku were smar to get what happened. The sub is Present Mic.