In the year of 1762, 35 years into the rule of King Yeongjo of the Joseon dynasty, Crown prince Sado is accused of plotting treason by his biological mother Lady Yi. King Yeongjo cannot penalize his own son as a traitor, as it would mean that he would become the father of a traitor threatening his throne, and ends up ordering Sado to take his own life. As Sado's lieges oppose King Yeongjo's decision by putting their own lives at risk, King Yeongjo locks Sado in a wooden rice chest to kill him.