Sejong and his father engage in a battle of the wits as young Ddol Bok struggles to survive in the Slaves' Quarters.

Ddol Bok rises to become a palace officer and changes his name to Kang Chae Yun in an attempt to get close to the king.

Assigned to investigate the recent murders, Chae Yun comes face to face with an assassin with superior skills to match his own.