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!
Time bomb Garo, a monster admirer, finally explodes, attacking the Hero Association! Meanwhile, Miss Blizzard visits Saitama at his apartment. Because of his lower rank, she plans to make him one of her subordinates, but…