「架空(梦想)」成为了「现实」!这是一个人类拥有超常能力"个性"已成日常的世界。遇上心中憧憬已久的No.1英雄.欧尔麦特的"无个性"少年.绿谷出久、人称「笨久」,被欧尔麦特看出其内心具有成为英雄的特质,于是决定让他继承自己的"个性"ONE FOR ALL(我为人人)。笨久进入英雄辈出的名校.雄英高中就读,为了成为活用其"个性"拯救众人的"英雄",跟着英雄科1年A班的同学们一同成长。时值笨久他们就读雄英的第二年春天。英雄们对死柄木等一伙敌人发起扫荡作战,战斗之激烈,可谓是"全面战争"。这场双方都付出极大代价的全面战争看似告一段落,但社会对于英雄的信赖却产生动摇,渐行荒废。身为ALL FOR ONE(人人为我)之目标的ONE FOR ALL继承者的使命感,以及那不想让周遭人士置于险境之中的想法,笨久决定离开雄英独自战斗。对于因焦躁而疲惫不堪的他伸出援手的,是那些1年A班的同班同学们。自己并非独自一人,雄英的英雄学生们下定决心一同去面对。而死柄木与ALL FOR ONE等敌人,为了歼灭英雄安排了下一项计画。"最终决战"的时刻将近。以及从美国飞来的另一位英雄…。究竟笨久一行人,有办法夺回大家那充满笑容的日常吗…。
In a world where possessing superpowers known as Quirks is the norm, Izuku Midoriya, who goes by Deku, is Quirkless. One day, however, he meets his idol and No. 1 hero All Might, who recognizes Deku’s innate potential as a hero and transfers his Quirk, One for All (OFA), to Deku. Enrolling at the prestigious U.A. High School, Deku strives to become a hero who can save society and people with his Quirk as he grows alongside his Class 1-A classmates. In spring of Deku and his friends’ second year at U.A., the Heroes carry out a search-and-destroy mission against Shigaraki and the Villains, resulting in a fierce battle that can be described as an all-out war. The fighting comes to a temporary halt with significant damage incurred by both sides, shaking the public's trust in the Heroes and leading society into turmoil. Motivated by a sense of duty as the successor of OFA targeted by All for One (AFO), and not wanting to endanger those around him, Deku leaves U.A. to fight alone. As he becomes increasingly desperate and worn out, his Class 1-A classmates lend him a hand. Realizing they're stronger together, the U.A. students and the Heroes unite. Meanwhile, Shigaraki, AFO, and the other Villains plot their next move to try and annihilate the Heroes. At last, the final battle approaches. Plus, another Hero comes flying in from America. Will Deku and his friends be able to bring back the days of smiles and laughter?