Kyung Soo is blind, but he is good at acupuncture. He is recognised for his talent by Lee Hyeong Ik and enters the palace. Around that time, Crown Prince So Hyeon, who was taken hostage by the Qing Dynasty, returned home after 8 years. While King In Jo is happy for his son’s return, he is also engulfed with anxiety for a while. Then one night, Kyung Soo, who can only see dimly in the dark, witnesses the death of Crown Prince So Hyeon. As he tries to tell the truth, bigger secrets and conspiracies are revealed, putting his life in jeopardy. After the death of his son, In Jo's anxiety turns to madness and begins to go wild. Kyung Soo, who witnessed the death of the crown prince, tries to uncover the truth behind it.