In this dark story of revenge, Bruce Lee"yields" as Billy Lo, whose bestfriend Chin Ku expires of a sudden illness. But feeling of foul play arises when a gang tries to sneak Ku's coffin at the funeral. When Lo's younger brother Lo hears about the episode, he renders his Buddhist master to investigate the reality. His trail soon leads him to Death's Castle, '' the place Chin Ku was seen alive. There, he befriends and meets an ally--a very cruel and merciless martial arts expert who is also the master of the tower. However, if the master dies under mysterious circumstances, Lo eventually ends up dueling with somebody far more terrifying.