Crown Prince Sado challenges No-Ron's power. In response, No-Ron conspires with the Qing Dynasty to frame Crown Prince Sado as conspiring a revolt. To save his son the Crown Prince Sado, King Youngjo and No-Ron agree to kill the Crown Prince's closest liaison, Baek Sa-Geong and use him as a scapegoat. Baek Sa-Geong, his family, and even his unborn child are to be all killed.
Right before Baek Sa-Goeng's beheading, he turns to his closest friend Kim Kwang-Taek, who is widely regarded as the best swordsman, and asks him to take care of his wife and unborn child. With the help of the swordsman Kim Kwang-Taek, Baek Sa-Goeng's pregnant wife is able to escape. Meanwhile, soldiers conduct a search for Baek Sa-Goeng's wife and her unborn child.
Baek Sa-Goeng's wife finally gives birth to a baby boy. Right after his birth, the mother dies. The baby boy is given the name Dong-Soo.
Soldiers arrive at the cottage to arrest the mother and her accomplices. Swordsman Kim Kwang-Taek and the newborn baby are captured. The new born baby is about to be thrown into boiling water when Crown Prince Sado arrives and show's the king's order which calls for the pardon of Kim Kwang-Taek, but not the baby. Kim Kwang-Taek pleads for the baby boy's life. He offers to to cut off one arm to save the baby, which is accepted.
Even after Kim Kwang-Taek loses his arm, the men attempt to kill baby Dong-Soo. KIm Kwang-Taek decides to flee to the Qing Dynasty with Dong-Soo. On the way, Kim Kwang-Taek is ambushed by assassins. Kim Kwang-Taek hides the baby Dong-Soo, before battling the assassins. When Kim Kwang-Taek comes back, the baby is gone. A man named Hwang Jin-Gi finds baby Dong-Soo in the mountain. Hwang Jin-Gi notices the cottage name inscribed in the baby's clothing and takes him back to the cottage where the baby was born. Hook Sa-Mo, friend of Dong-Soo's father, raises Dong-Soo. By the age of 12, Dong-Soo's health has become poor. He can't run or even raise his hands. He is always teased by the other kids.
Meanwhile, when Yeo Woon was born, his father Yeo Cho-Sang attempted to kill him, because he saw his son's fate as a killer of many people. Yeo Woon's mom is killed, while trying to protect Yeo Woon. 12 years later, Yeo Cho-Sang raises Yeo Woon, but without love. Yeo Woon practices sword fighting by himself. One day, he is picked by Chun and trained by the group "Hoksa Chorong".