The second prince asks about the investigation into the disappearance of his son. He learns that the informant from the marquis's mansion has told him that the old man is suffering from a strange illness. The informant also tells him that he must drink blood at full moon night every month. The old marquis wants his son to inherit his military career, so he doesn't want to tell the emperor or the second prince about the illness. He also tells the prince that the emperor hasn't felt well recently, so the emperor has given him authority to handle the matter. The prince tells the informant that he should hold a banquet for his highness and the emperor at the same time. If the plan fails, the informant tells him, she will die. The next day, the prince tells his brother that the duke's son has returned from a long trip. The brother asks if he still likes him, and the prince replies that he does not. He tells the brother that he wants to see his son as they haven't been seeing each other for a long time, and he asks him to invite him to the banquet. He explains that the banquet will be held just three days after his son returned from his trip.