Yuan Tiangang was born with a fate of abandonment. After his family members died in exile, he went to Cangbing Valley to seek refuge with his uncle. When he was 15 years old, the world was in chaos. Cangbing Valley, which was responsible for protecting the Longyuan Sword, was slaughtered by the evil spirits. When he opened his eyes again, he saw graves all over the mountain. From then on, he decided to gamble with his life. He learned the art of fortune-telling by weighing bones, became a killer, and specialized in killing people whose lives were not supposed to end. At the age of 35, he met Huanyin, the proprietress of an inn who hired a killer to kill people in a small town on the northwest border. Huanyin was outnumbered in assassinating Li Yuan. When Yuan Tiangang came to rescue, he met his old friend Li Chunfeng. From then on, Longyuan reappeared in the rivers and lakes, and Yuan Tiangang's identity as the guardian was made public. Should he shoulder the responsibility of protecting the dynasty, or return to the rivers and lakes to be a chivalrous and righteous traveler? The story of the Bad Commander is unfolding...