Li Yu is teaching Princess Yun Chuan how to play the piano, because Yun Chuan needs to perform it at the banquet. Her performance is not very good, so Li Yu said that he built another new piano which will make her performance better.
Dong Rushuang and Xie Beiming knew that Pei Zhao was going to marry Yun Chuan. The two were very angry, and Feiyueyuan told them that Pei Zhao had done everything to save Su Ci. Pei Zhao said why he wanted to marry the princess, Pei Zhao said that he had no other way.
When the princess came to Pei’s mansion, Pei Zhao specially prepared cheese for her. Princess Yunchuan was very happy. Said that he wanted to return the gift, so he played a live song. At this time, the people in the prison were talking about the imminent marriage of King Qi and Princess Yunchuan. Su Ci was sad to hear that this was Pei Zhao’s method.
After playing the piano, the princess felt unwell and vomited blood. The doctor said that the princess was poisoned, but he had never seen it before and did not know how to detoxify. If the poison is not interpreted in time, it will not last for five days. Pei Zhao said that Yunchuan should not be moved, and Shumu said that because Yunchuan was poisoned in the palace, he should not stay in the palace again. And let them find the real culprit, if Yunchuan has an accident, he will fight Daliang to the death.
Director Liu Xuan of the Department of Derby began to investigate the maids and servants in Pei Zhao’s mansion.
King Yun told the emperor Prince Shumu, King Yun said that if Bei Rong and Liang go to war, the people will be in fire and water. It was also said that Princess Yunchuan was the poison in Pei’s mansion, and Pei Zhao could not shirk the blame. The emperor ordered King Qi to be placed under house arrest. Yun Chuan woke up but still vomited blood, the doctor said Yun Chuan’s poison was more serious.
Pei Zhao understands that if there is something wrong with Princess Yunchuan, he will not only be unable to save it, but will also lead to war between the two countries. So Pei Zhao broke into the palace at night and asked the emperor to let Su Ci go to investigate the Yunchuan poisoning case, and the emperor agreed.
On the next day at the court, King Yun disagreed. Liu Xuan believed that he needed to find out the truth and argue with King Yun, but the emperor’s imperial decree had already been issued and could not be taken back.
The father-in-law took the imperial decree to the cell and asked Su Ci to investigate the poisoning case of Princess Yunchuan. The emperor also asked Rushuang and Su Ci to detoxify Yunchuan together. Su Ci came to the post house and said that he would do his best to investigate the truth. Prince Shumu said that it would never be poisoned in the post house, and Der Spiegel also found out that no poison was found in Pei’s house.
Dong Rushuang said that the princess had been poisoned a few days ago, and that it was chronic poison, and that the poison became unbearable over time. Rushuang said that he still has no way to detoxify and needs to go back and study again. At this time, someone was listening to them outside the door.
Su Ci said that only someone close to her can poison Princess Yunchuan every day. Princess Yunchuan’s maid, Xiaoyue, said she was not herself. Su Ci wanted to draw the snake out of the cave, claiming that the princess was fine and could marry King Qi immediately.
Shumu took Yunchuan away, and Su Ci pretended to be Princess Yunchuan. Su Ci said it was his duty. Su Ci wondered whether it was the murderer who poisoned herself, and Yun Chuan approached and caused the poisoning. Su Ci noticed the white particles on the eaves. The next person explained that termites had appeared, so he applied the paint again.
Pei Zhao came to find Su Ci. It turned out that Pei Zhao had been to Shuomu before and let himself participate in the investigation. Su Ci said that Pei Zhao wanted to marry Yun Chuan for himself, but it was someone else’s husband after all. Now it is more important to find the murderer and resolve the crisis between the two countries.
Sakumu and Rushuang also came in. Pei Zhao noticed the piano on the table. At this time, everyone was discussing how to be poisoned. At this time, Xiaoyue suddenly fainted, Rushuang said that Xiaoyue was also poisoned. Pei Zhao said the room had a strange smell, but it was not all Yunchuan’s favorite thyme. Su Ci told Shumu that it was time to act.