Boku no Hero Academia 3rd Season 573j4u

Synopsis 703b1

Twice observes the changes in society after All Might's retirement, noting how the combination of All Might's absence and public unease of Endeavor taking his place has caused a surge in villain activity. He also reflects how irresponsible use of his quirk caused him to be eternally uncertain if he is real or a copy of himself, and that the League of Villains is the only place that would accept a damaged person like him. He then witnesses a villain named Overhaul kill another group of villains. Meanwhile, U.A. holds its opening ceremony, where the Principal announces that the first year students will be beginning "hero work studies" earlier than usual due to the rising villain threat. Midoriya returns to class after he serves his house arrest, where Aizawa introduces the Big Three, the top three students of U.A., who will be helping Class 1-A with their hero work studies.

(Source: Wikipedia)