The ability to perfectly copy martial arts, Superior Interior Power! Qin Tianlang, who was branded as the "World's Greatest Killer," met a miserable death because of this ability. When he woke up, he had possessed the body of his son, Nam Gungcheon, who had committed suicide three days ago. Nam Gungcheon, who had been deeply despised because he was the son of the "World's Greatest Killer". "This time, I will become the "First Heavenly Dragon" in my son's name and take revenge on the world."