"Warrior Baek Dong-soo" is based on the life of Baek Dong-soo, the strongest knight in the Joseon Dynasty, and tells the story of the battle between the king's personal guards and the assassin group. Baek Dong-soo, played by Ji Chang-wook, is a warrior in the era of Yeongjo and Jeongjo of the Joseon Dynasty. He once compiled the "General History of Martial Arts". Together with the guards of King Jeongjo, he competed with the warriors of the opposing assassination organization "Black Candle Cage". Yu Yun, played by Yu Seung-ho, is the top swordsman in Joseon. He is proficient in martial arts, swordsmanship, gunmanship, boxing, and riding. He is the core figure of the secret organization "Black Candle Cage" that assassinated Jeongjo. The duel between the two will rise to a bloody storm between Kim Gwang-ryul, the sword god of Joseon (played by Jeon Kwang-ryul) and Cheon (played by Choi Min-soo), the strongest master of the black lantern.