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!

Hero hunter Gato intensifies his onslaught, so of course Saitama decides now is the perfect time to join a combat tournament. Meanwhile, Class-S hero Metal Bat takes an assignment guarding a Hero Association executive and his son, and before long trouble appears!