As summer arrives for the students at UA Academy, each of these superheroes-in-training puts in their best efforts to become renowned heroes. They head off to a forest training camp run by UA's pro heroes, where the students face one another in battle and go through dangerous tests, improving their abilities and pushing past their limits. However, their school trip is suddenly turned upside down when the League of Villains arrives, invading the camp with a mission to capture one of the students. Boku no Hero Academia 3rd Season follows Izuku Deku Midoriya, an ambitious student training to achieve his dream of becoming a hero similar to his role model—All Might. Being one of the students caught up amidst the chaos of the villain attack, Deku must take a stand with his classmates and fight for their survival.

The stage this time is the UA dormitory, taking place just before the Endeavor Internship arc. Third-year Mirio Togata appears suddenly as the first-year students in Class A are bored during their ban from going outside. He brings with him the card game Yuuei Heroes Battle, created by the support class. As each student picks cards and joins the fierce battle, there seems to be more to the game than meets the eye. At the end, who will emerge victorious? (Source: ANN)

Episode 1 is based on one-shot manga released in Vol. Origin, it explores the back-story of All Might's past and his journey into becoming the No.1 hero. Episode 2 is an epilogue picture drama for Boku no Hero Academia the Movie: Futari no Hero. Short specials included with the Blu-ray/DVD release of Boku no Hero Academia the Movie: Futari no Hero.

U.A. High School's students of Class 1-A have made it to summer break. Izuku Midoriya accompanies his mentor All Might to a celebratory superhero festival on I-Island, an isolated patch of land dedicated to researching Quirks and everything else associated with the hero business. Midoriya is granted the opportunity to meet All Might's friend Dave and Dave's daughter Melissa, two talented hero equipment engineers. He also encounters his classmates, most of whom have been given the opportunity to spend part of their summer break at the festival. However, a mysterious squad of villains infiltrates I-Island, and it is up to Midoriya and his friends to confront them, using their developing Quirks to fight off the new enemy and uncover a treacherous plot.