Ji Pyeong is murdered, and Prince Yeoning is witnessed to be the murderer and it arrested by Saheonbu. He is investigated by Saheonbu but is not willing to speak the truth. Meanwhile, behind the murder cases are what is known as master-murderers and the murderer of Ji Pyeong turns out to be a little girl wearing a tattoo. Moon Soo and Yeo Ji investigate what's behind the murder cases.