Legendary dragon Ishimi helps Cheonyeong the human emperor gain power, only to be betrayed and get trapped in a cave for 500 years. Then he receives an unexpected visitor, a young prince named Cheonseo who looks exactly like Cheonyeong and takes a liking to Ishimi. Determined to get revenge on Cheonyeong's descendant, Ishimi plans to use Cheonseo's blood to regain his strength. But the more Cheonseo visits him, the more Ishimi grows attached to his only visitor. Which will prevail, the dragon's burning desire for vengeance or his budding affections for the prince who loves him?