In the third episode of Princess Zhu Huan, which episode is the head injury of the swallow? Why are you hurt?

In episode 18, I was injured because Zhihua and the emperor were discussing calligraphy in Jingyang Palace. When it comes to swallows, he knows nothing ... At this time, swallows already know that the emperor is an enemy who killed his father. Seeing that they thought of their parents' tragic ending, they planned to take revenge. May accidentally pushed the swallow and hit the table to stop it. ...