The play tells the story of Zheng Ke, the best assassin in Jianghu, who enters the palace to assassinate the emperor in order to avenge his father's death, but he never expected that a huge conspiracy was about to be revealed. Zheng Ke, who was hiding in the palace, accidentally exchanged bodies with the beloved princess Qi Wan'er, so the two began to work together to find a way to exchange back. As they got to know each other better, they went from suspicion to mutual protection and mutual understanding, gradually strengthening their feelings for each other, and also joined hands to overthrow the prime minister's conspiracy of rebellion...