Episode 21 recap: Nan Si stabbed Cang Han Yu.

Nan Si expressed that the person he despised the most was someone who had deceived him. He could either treat Cang Han Yu kindly or discard him completely. Cang Han Yu stated that he had not deceived Nan Si and that everything was Nan Si's own doing.Nan Si took a knife and stabbed Cang Han Yu, indicating that Cang Han Yu dared to deceive him, and this was the price Cang Han Yu had to pay. Nan Si ordered others to drag Cang Han Yu's body to the back mountain to feed the dogs, as a way to show them the cost of betraying him.

The National Teacher witnessed all of this and went to find Cang Yunze, informing him that he had personally witnessed Nan Si killing Cang Han Yu. Cang Yunze believed that this time neither Nan Si nor Cang Han Yu had any memories, which was why things had turned out this way. He had to personally capture Nan Si and make him suffer before his eyes.

The National Teacher went to the Empress and told her that Nan Si had acted decisively and understood the greater good. He hoped that the Empress could help Nan Si celebrate his 20th birthday and present him with the national treasure, the Phoenix Hairpin, and appoint him as the Crown Prince. The Empress found it reasonable. Cang Yunze gathered his people here, stating that they would definitely conquer the Eastern Lan Kingdom this time.

Nan Si was practicing swordplay in the residence when the Emperor came to find him and asked if he was feeling upset. Nan Si replied that it was nothing and asked why his father had come. The Emperor handed Nan Si the Phoenix Hairpin. Nan Si was also very surprised to see it.