This movie was the first one the Shaw Brothers shot in1967. Directed by Chang Cheh and scripted by Ni Kuang, this fast-paced, intensively plotted movie not only established the leading position for the movie company but also won the director a good reputation as a million dollar box office earner. This movie and the movie 'Come Drink With Me' started the new style of the wusia movie. It starts with Jimmy Wang (Wang Yu) as Fang Gang, Chiu Gaau (Jiao Jiao) as Siaoman, Poon Ying Chi (Pan Yingzih) as Ci Pei, Che Lui (Jheng Lei) as Deng Chong, and Zeng Miu (Jing Miao) as the antagonist, Changbi Shenmo meaning "The Long Arm Monster".

      The theme of this movie concerns a young man who avenges his foster father. Fang Gang's, the protagonist, foster father is Ci Rufong, who is also Fang's martial arts teacher and the head of the martial arts institute, Changfong Tang. Fang's biological father, Fang Cheng, was Ci's ex-subordinate; Cheng was killed in a battle when he tried to protect Ci, so Ci adopted Fang and let him study wugong in Changfong Tang.

      Ci's daughter, Ci Pei, and two elder fellow disciples always take advantage of Fang Gang. One day Fang beats Ci Pei in a bare-fisted boxing drill. Ci Pei, feeling embarrassed, impulsively takes a sword and chops off Fang's right arm. Fang dashes out immediately, and instead of asking his acquaintances for help, he runs away from home to the countryside. Fortunately he is rescued by a village girl Siaoman. Fang wants to spend the rest of his life with Siaoman, but the assault from gangs stimulates him to arm himself again. He always wakes up at mid-night to practice wugong; Siaoman reluctantly gives him her father's precious sword book. The wugong recorded in this book is very strange, as it requires a short sword. Fang finds a half-broken sword his father left matching the requirement, so this sword becomes his weapon.

      One day he and Siaoman attend a religious fair held at the site of a temple. They come across the scene that Ci Pei and the elder fellow disciples are abducted. Fang runs to rescue them although Siaoman wants him to keep away from fighting.

      Ci Rufong proclaims his retirement on his 55th birthday. He also wants to find a capable newcomer to be his successor, as the head of the Changfong Tang. However, his long time rival, Changbi Shenmo, also chooses this day to start an attack to get rid of Changfong Tang once and for all.

      Fang and Siaoman always want to keep themselves away from the martial arts circle, but this time they meet a seriously wounded senior disciple of Changfong Tang in the inn where they happen to be staying. The senior tells them that Changbi Shenmo intend to kill all the members of Changfong Tang, so Fang decides to fight for his masters and old fellows. The final fight is in Changfong Tang. The one-arm Fang becomes the hero who saves Changfong Tang, the place where he grew up. Ironically, the wugong, which he uses to defeat Changbi Shenmo, is not what he learned from Changfong Tang, but it was what he learned from Siaoman, and the weapon was what his father left behind.