A single man arose to face the evil threatening humankind!
His name was Saitama. He became a hero for fun.
Saitama went with Genos to take the professional hero exam and passed with flying colors on his first try! Now he begins his service as a new Class-C hero.
But he wasn't aware of his quota of one heroic deed per week, so he is suddenly faced with the crisis of losing his registration! As he races around town looking for trouble, he runs into Speed-o'-Sound Sonic. Sonic wrecks havoc on the city, and Saitama defeats him, but...
- Black Sperm makes a cameo as an ice shaver in this volume.
- The original version of Chapter 21 featured several full-color pages and flipbook animations. These were all removed in the volume release due to printing limitations, making the color pages black-and-white and condensing the animations into fewer panels.
- Stinger's original design - wearing a vest and belt - was redrawn to be consistent with his updated design. His fight with the Seafolk was also shortened.
- Errors remain on pages 20 and 21 of Chapter 23 which show Stinger with his old design's shoulder pads.
- An error in Chapter 22 where Saitama appeared shirtless in several panels was fixed.