Song Ci (played by He Bing) passed the imperial examination in Beijing and was ready to go to the border town with his good friend Meng Liangchen (played by Wu Jun) after returning home to get married. However, Song Ci's father Song Gong had not returned home until the day of the wedding. When the two newlyweds were worshipping, a carriage brought back his father's body. Song Gong had been engaged in criminal investigation all his life and had never made a mistake, but he failed because of a misjudgment of a life. This was a death apology, and he also left a suicide note prohibiting the descendants of the Song family from getting involved in criminal investigation. Unexpectedly, misfortunes never come alone. The bad news that Meng Liangchen was murdered on his way to take office came back. Under the persuasion of his mother, Song Ci moved to the border town to find out the case for his best friend and clear his name. As a result, Song Ci was promoted to the sixth rank of the Dali Temple, and was later appointed to the prison in other provinces. Song Ci successively investigated and solved a series of unsolved cases, including the "Taiping County Unjust Case", the "Li Mansion Serial Case", the "Maozhuwu Headless Case", the "Chengnan Well Corpse Case", the "Lost Fan Framing Case", the "Liang Yu Life Case", and the "Li Yugu Disappearance Case".