

The seemingly unimpressive Saitama has a rather unique hobby: being a hero. In order to pursue his childhood dream, Saitama relentlessly trained for three years, losing all of his hair in the process. Now, Saitama is so powerful, he can defeat any enemy with just one punch. However, having no one capable of matching his strength has led Saitama to an unexpected problem—he is no longer able to enjoy the thrill of battling and has become quite bored. One day, Saitama catches the attention of 19-year-old cyborg Genos, who witnesses his power and wishes to become Saitama's disciple. Genos proposes that the two join the Hero Association in order to become certified heroes that will be recognized for their positive contributions to society. Saitama, who is shocked that no one knows who he is, quickly agrees. Meeting new allies and taking on new foes, Saitama embarks on a new journey as a member of the Hero Association to experience the excitement of battle he once felt.
Eighth-grader Shigeo "Mob" Kageyama has tapped into his inner wellspring of psychic prowess at a young age. But the power quickly proves to be a liability when he realizes the potential danger in his skills. Choosing to suppress his power, Mob's only present use for his ability is to impress his longtime crush, Tsubomi, who soon grows bored of the same tricks. In order to effectuate control on his skills, Mob enlists himself under the wing of Arataka Reigen, a con artist claiming to be a psychic, who exploits Mob's powers for pocket change. Now, exorcising evil spirits on command has become a part of Mob's daily, monotonous life. However, the psychic energy he exerts is barely the tip of the iceberg; if his vast potential and unrestrained emotions run berserk, a cataclysmic event that would render him completely unrecognizable will be triggered. The progression toward Mob's explosion is rising and attempting to stop it is futile.