The story takes place in 19th century Korea, where a ship carrying tribute was suddenly engulfed in flames on Donghwa Island. To investigate the truth behind the incident, the court dispatched investigator Lee Won-gye (played by Cha Seung-won) to the island. However, shortly after their arrival, a murder occurred, and the state of the victim was so horrific that it was difficult to look at. Soon, the murderer was apprehended, but afterward, including the captured murderer, the number of dead kept increasing, which meant that the mastermind behind the case was still at work. Furthermore, rumors spread about the spirit of Commissioner Ahn, who had been wrongfully killed seven years ago, causing those who fell victim now to be intricately connected to the events of that time. Lee Won-gye teamed up with painter Doo-ho (played by Ji Seung) to investigate, but they struggled to find any leads.