The titular weapon is reputed to be the most powerful in the martial world, easily besting all other swords, and many have died in their quest to possess it. The learned, one-armed master of the Yuan Mountain school (Tien Feng) instructs students Yu Chien-wan (Chang Yi, in his first lead role) and Chiang Kwun-yuan (Lo Lieh) to locate The Thundering Sword so that he may destroy it. The pair decide to split up, and Kwun-yuan discovers The Sword (which has a jet black blade) inside a booby-trapped tomb. However, just after he succeeds in liberating it, haughty swordswoman So Jiau-jiau (Cheng Pei-pei) snatches the weapon from him. A member of the Wu Du clan (an apparent mistranslation of Wu Tang), Jiau-jiau is attracted to Chien-wan, who is unaware of her fiery nature and willingness to kill with little provocation. Regardless, her love for this rival clansman is so great that she decides to help him return The Sword to Yuan Mountain, despite the fact that two Wu Du leaders (Chan Hung-lit and Wu Ma) seek to claim the weapon themselves. Further complications arise when another master (Ku Wen-chung) insists that the Yuan elder duel with him to determine who should rightfully possess The Sword. Jiau-jiau’s past indiscretions also threaten to destroy her proposed marriage to Chien-wan.

Time has not been kind to this martial melodrama, which features exaggerated interpretations and circumstances right out of the ripest Peking Opera. Director Hsu Cheng-hung even incorporates three songs and that, plus the near complete reliance on "interior exteriors," makes the whole thing seem even more like an offshoot from the stage. Chang Yi’s innocuous performance makes it clear that his later switch to villainous roles was the right career choice, and there is so much tragedy, one half expects the surviving cast members to complete the cycle by falling on their swords. During the incredibly drawn out climax, one character is driven to exclaim, "What a coincidence!," a thought that more than a few of the audience members were no doubt experiencing by that point. The music is constantly overwrought; those who love American horror movies may find the choice of library cues (including music originally composed for THE BLOB and a track used in many of Andy Milligan’s cheapo historical horrors) either amusing or gratingly inappropriate.

There are some scant good points, however. Cheng Pei-pei’s performance is as affected as her fellow cast members, but the actress’ characteristic radiance makes the viewer care about her character, even as the contrivances mount. Lau Kar-leung choreographed the martial arts (which feature some very dated wirework, but one impressively staged massacre) and can also be seen briefly as a would-be assassin wielding a bow and arrow. The supporting cast (including Ku Feng, Ching Li, and Shu Pei-pei) is also stocked with quality actors. Ultimately, those who collect Huangmei Opera films will probably be the most receptive audience for this title and they may wish to adjust the rating up a star or two.