While interrogating Mei Changsu, Xia Jiang forces down a Wujin poison pill, so that he would do his bidding. Xia Dong also sees his master do the deed and questions Xia Jiang's actions. Prince Ji tells the Emperor about seeing Xia Dong with Wei Zheng on the day of his capture, causing him to suspect the Xuan Jing Bureau; the Emperor asks Meng Zhi to covertly bring Xia Dong in for questioning. Xia Dong confesses that it was her who kidnapped Wei Zheng. (Source: Wikipedia)