Saitama started his three-year special training to be the unbeatable hero of the town. He dreamed of being a hero and became invincible who beating enemies with just one punch. Along with his loyal student, Genos, Saitama serves the Hero Association.
One day, monsters of the Monster Association kidnap the child of the hero association executive. So the top S-class heroes decide to rescue hostages by attacking the monsters. While Garou, a human monster, is also captured by them, he wakes up in their hideout.
