Raised by monsters in a battle-scarred world, Dai has the heart of a hero! He sets off on a grand journey with brave friends, traveling the world to take down the Dark Lord's minions. Along the way, Dai must awaken the hero he was meant to be and master his dormant powers.

Before his adventure begins, Dai lives in peace as the lone human among monsters on Dermline Island. While he dreams of becoming a hero, a group of fakes shows up to kidnap the Golden Metal Slime! Then, when Princess Leona arrives in need of a hero, Dai is ready to answer her call...but he needs more training! Will a tutor come along to help him?