In the fourth year of Chuigong, Di Renjie was appointed as the governor of Jiangnan. During an inspection in Lin'an County, he encountered a case of chaos. The old man Meng Yunde sued his uncle Li Dayou for killing his daughter Meng Xianglian and son Meng Yang, while Li Dayou counter-sued his father-in-law for hiding Meng Xianglian and intending to marry someone else. It turned out that Meng Xianglian and Li Dayou went back to her parents' home in a quarrel. After Meng Xianglian returned to her parents' home, Li Dayou's mother fell ill in a rage, and Li Dayou had no choice but to ask Meng Xianglian back to take care of her. Li Dayou came to Meng Xianglian's house and persuaded her in every possible way. Meng Xianglian agreed to go back, but it was late and she could only wait until the next day for her brother Meng Yang to send her back. Li Dayou was worried about his mother, so he rushed back that night. However, after a few days, Meng Xianglian did not come back. Li Dayou went to ask for her again, but was told by his father-in-law that the two had left long ago. Two living people disappeared without a trace, and Li Dayou suspected that his father-in-law had hidden his wife and wanted to marry someone else. Meng Yunde also suspected that Li Dayou had killed his wife and son. Lin'an County Magistrate Zhou Congshan didn't know what to do and could only ask Di Renjie for help.