In the time of enlightenment, a battle between a sword and a gun has started.Based in the time of enlightenment of 17th-century Joseon, This drama tells the story of Joseon's last swordsman named Park Yoon Kang who grabs a gun ditching his sword and grows to become the era's hero. Park Yoon Kang is the illegitimate son of the best swordsman in Joseon. After his father and sister get killed, he trades sword for gun as he embarks on his revenge mission.