Which episode is the swallow learning from Princess Xiang?

In episode 12, the queen learned that the swallow had been stung by a bee and came to Shufangzhai to see a joke. Not content, the swallow cleverly stuffed the petals into the queen's hat. As a result, when the queen came to the imperial garden, a group of bees attacked the queen and Sister Rong again. When she saw the queen, she turned pale with fear, but the swallow and the others smiled happily. Er Kang, Wei Zi and others carefully planned a wonderful program to celebrate the emperor's birthday, which surprised Gan Long. However, just as everyone was immersed in a happy birthday, they found evidence of the murder of Gan Long in Shu Fangzhai. Zheng Xiaoyan, Wei Zi and others could not argue, and all the servants were immediately put into prison.