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!

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!