Hou Chi and Qing Mu encounter Sen Jian and Chang Qin, who were once betrothed until a fox demon, Qing Li, came between them. They pretend to be doctors from the Fox clan to heal Qing Li so they can enter Xuanjing Palace to look for Zi Yue. Feng Ran tries to get rid of Jing Jian, but they accidentally activate the spirit lock, binding them together. (Source: frankly at MyDramaList)