One hundred years after the Hero Yoshihiko defeated the demon king, evil has been released back into the human world. But Yoshihiko's descendant refuses to save the world, so Yoshihiko's group is resurrected - incompletely, it turns out.
Yoshihiko's group begins their search for keys to lock away evil spirits. One of those keys belongs to a village whose princess has been kidnapped by bandits.
Yoshihiko's group leans of a key that will be the grand prize in a Martial Arts Tournament. Yoshihiko agrees to participate in the tournament but runs into an extremely powerful fighter.
Yoshihiko's group meets a group of monsters that takes on their appearance, and starts a wild chase after their impersonators so that they don't ruin their reputation.
Yoshihiko falls asleep when fighting a bandit, and later tries to run away with a married women. The other three start betting and playing around in a casino.
For the final battle Yoshihiko's group goes to Estas village to get equipment, but the equipment maker sends them to Evil Mountain for materials, and there they encounter three troublesome bandits.
Yoshihiko's group is greeted by a monster with overly long insults that routs them. They later end up in a modern city and Yoshihiko starts a radio station.
The final battle commences, but Yoshihiko's group must defeat the Monster Emperor with help from his good twin whose testicles provide the key to the Monster Emperor's defeat.