Having taken down such villains as a crabby creature and a mosquito girl, superhero Saitama meets Genos, a cyborg who wants to discover the secret to his strength Life gets pretty boring when you can beat the snot out of any villain with just one punch.
Nothing about Saitama passes the eyeball test when it comes to superheroes, from his lifeless expression to his bald head to his unimpressive physique. However, this average-looking guy has a not-so-average problem—he just can’t seem to find an opponent strong enough to take on!
Saitama’s easily taken out a number of monsters, including a crabby creature, a malicious mosquito girl and a muscly meathead. But his humdrum life takes a drastic turn when he meets Genos—a cyborg who wants to uncover the secret behind his strength!