Dori is the only son of the old man Park Shin, a kind, brave, and adventurous child. In the village of Dal-an, a wicked magistrate was seizing the property of innocent citizens, and old man Park's house was no exception. Dori heard his father say that by wearing the goblin's hat, one becomes invisible. He thought that if he could get his hands on the goblin's hat, he could correct the bad habits of evildoers and rescue Kim Jin-sa, Ok-hee's father, who was unjustly imprisoned. After countless hardships, Dori obtained the goblin's hat. He corrected the magistrate's bad habits and rescued Kim Jin-sa, but accidentally the hat fell into the hands of evildoers, causing people to be harmed instead. However, with Dori's cleverness, he retrieved the hat and restored justice.