Saitama is a hero who only became a hero for fun. After three years of special training, though, he’s become so strong that he’s practically invincible.
In fact, he’s too strong that even his mightiest opponents are taken out with a single punch, and it turns out that being devastatingly powerful is actually kind of a bore.
With his passion for being a hero lost along with his hair, yet still faced with new enemies every day, how much longer can he keep it going?
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.