在这部铁娃动作/剧情片中,民国初年，爱国人士代表蔡氏向袁世凯痛陈廿一条不平等条约之利害，竟被扣押监禁。为营救蔡，革命党人多方奔走，却徒劳无功。后查悉侦缉队队长雷天宝有一胞妹玉英在山东，并派革命党人杨刚前往找寻。雷与其妹自幼被王大妈收养，革命党人希望玉英混入侦缉队刺探消息。岂料玉英早已夭折，王之义女陈小英，得知内情后，自告奋勇假冒玉英前往做内应。雷喜获兄妹重逢，安顿大妈及小英居雷家。无意间，小英得悉侦...
A female revolutionist takes on the identity of a Captain's long lost sister who is actually dead. She manages to fool the Captain for a while, but the Captain soon catches on to her and the plan to stop Chinese-Japanese relations.
