<p>　　里昂（让·雷诺饰）是名孤独的职业杀手，受人雇佣。一天，邻居家小姑娘马蒂尔达（纳塔丽·波特曼饰)敲开他的房门，要求在他那里暂避杀身之祸。原来邻居家的主人是警方缉毒组的眼线，只因贪污了一小包毒品而遭恶警（加里·奥德曼饰）杀害全家的惩罚。马蒂尔达得到里昂的留救，幸免于难，并留在里昂那里。里昂教小女孩使枪，她教里昂法文，两人关系日趋亲密，相处融洽。 &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;　　女孩想着去报仇，反倒被抓，里昂及时赶到，将女孩救回。混杂着哀怨情仇的正邪之战渐次升级，更大的冲突在所难免……</p>