[Washing Away Wrongs] is based on a book written during the Song Dynasty (1247 AD), "Washing Away Wrongs". This amazing work in the history of forensic medicine records the life of Song Ci, a pioneer of Chinese forensic medicine, and how he unraveled the strange cases that shocked the court and the public at that time. Song Ci (played by Bobby Au-yeung) was born in a coffin and was ridiculed as a "coffin boy" and suffered discrimination. However, he was optimistic and positive and was never affected. He was a happy night watchman. Until he and the chivalrous woman Tang Si (played by Jessica Hsuan) were involved in the murder of the village chief and sentenced to death, he was helped by the new county magistrate Song Yi in the process of solving the case. In addition to redressing his grievances, he was also hired as a coroner. After that, the two joined forces to solve strange cases again and again. Tang Si and constable Nie Feng (played by Chen Miaoying) both have a crush on Song Yi, but Song Yi marries Lan Caidie, a daughter of a wealthy family. Song Yi's intelligence and honesty gradually impress Tang Si and Nie Feng, but then news comes that Tang Si is actually a princess. At the same time, Song Yi's behavior arouses his parents' suspicion: Is he... not the real Song Yi?