A scamp Sang-hyeon who has crush on Hui-jeong shadows her to her house. He sneaks into her home and is surprised by a ghost. He stabbs the ghost who turns out Hui-jeong's mother. Hui-jeong gets married to Yeong-min and lives together with her father who has nobody to turn to. But Yeong-min's mother hates her daughter-in-law and mistreats her. She in the end kills Hui-jeong's father and attempts to kill Hui-jeong. Her dead mother appears to save Hui-jeong from the wicked mother-in-law.

During the later years of Goryeo Dynasty (918-1392), a talented martial artist is murdered. His resentment makes him born again as Bulgasari, a monster that grinds and eats up iron. The monster takes his revenge on the traitors responsible for his death.