The dying master of the powerful Poison Clan dispatches his last pupil, Yang Tieh, on a crucial mission. Worried that the skills he has taught are being used to evil ends, he orders Yang to trace a retired colleague, Yun, and warn him that the fortune he amassed from the clan's activities is under threat from five of his former pupils, each an expert in his own lethal combat style. Yang must discover the whereabouts and true identities of these masked warriors, and decide which, if any, he can trust to join him in his mission. The five pupils are the Centipede, Snake, Scorpion, Lizard, and Toad. Centipede and Snake were the master's first and second pupils and they knew each other. Lizard and Toad were the fourth and fifth pupils respectively and they knew each other but Scorpion, the third pupil was unknown to the other four members. Before he dies, the master teaches Yang the weaknesses of each style.