Episode 19 recap: Cang Han Yu went to see the National Teacher.

Someone handed Cang Han Yu a packet of poison, claiming that it was given to him by the National Teacher. Cang Han Yu asked how to use it, and the person said to put it in wine or tea, and whoever drinks it will die immediately. Cang Han Yu went to find the Doctor and informed him that the real Seventh Prince had already died on his way here. The National Teacher asked why Cang Han Yu had come, and Cang Han Yu said he came to help him.

The National Teacher met Nan Si and Cang Han Yu here and said that he had calculated that there might be some issues with the Empress recently, but he had already found a way to resolve them. Nan Si asked if Cang Han Yu had any problems, and Cang Han Yu hesitated but decided that he hadn't figured out the situation yet, so he didn't tell him and said he had no problems.

The National God thought that as expected, Cang Han Yu was not the real Seventh Prince. Cang Han Yu went to find the National Teacher and informed him that the real Seventh Prince had already died on his way here. The National Teacher asked why Cang Han Yu had come, and Cang Han Yu said he came to help him. The National Teacher said that as long as he could become the Emperor of the Southeast Kingdom, he would let Cang Han Yu become the Prince of Xiling.

Someone came to find Cang Han Yu, and Cang Han Yu pretended to go to the restroom and came over first. The person handed Cang Han Yu a packet of poison, claiming that it was given to him by the National Teacher. Cang Han Yu asked how to use it, and the person said to put it in wine or tea, and whoever drinks it will die immediately.

At the banquet, the National Teacher intercepted the Empress's wine, saying that it was poisoned, and it was poisoned by Cang Han Yu. Cang Han Yu admitted that the National Teacher did give him a packet of poison, but he didn't actually use it. The National Teacher, of course, wouldn't admit it and claimed that the current Seventh Prince was an imposter and a spy.