On the border of the Middle-earth, the seventh prince of Yue, Xun Yuan, was said to be the son of the old emperor and a witch. He was looked down upon by others since he was a child. When the crown prince Xun Jiang came of age, he rebelled and usurped the throne. In order to protect the kindest and most innocent seventh prince Xun Yuan from the internal struggle for the throne, the old emperor took the opportunity to demote him to a commoner and made him a county constable in Jinyuan County. After Xun Yuan arrived in Jinyuan County, he encountered several bizarre cases in succession. With his extraordinary talent, Xun Yuan was able to solve the case quickly every time and was deeply loved by the local people. He also gradually impressed Shao Yue, a female coroner in Jinyuan County, and the two secretly fell in love. During the investigation in Jinyuan County, Xun Yuan accidentally obstructed the Crown Prince Xun Jiang's plan to rebel and usurp the throne many times. Xun Jiang arranged his confidants to find the treasure place of the Yue Kingdom's dragon vein in Sangeng Mountain. Some recent bizarre cases were caused by his men looking for the treasure place. Xun Yuan, after several life and death experiences, teamed up with the coroner Shao Yue's former head of police Shen Liang to thwart the conspiracy of the Crown Prince Xun Jiang. Finally, Xun Yuan ascended the throne and became the new emperor of Yue Kingdom.