A woman's sanity comes into question, after she claims to have witnessed a murder from her apartment window.

私人侦探迈克·汉默为他深爱的女秘书之死而终日酗酒流落街头，而他的旧日警察朋友带来的惊人案情使他重振旗鼓：女孩没有死，却有叫做“龙”的神秘人在追杀她，更有名为“蝴蝶二号”的组织牵涉在内。风姿绰约的年轻寡妇、同一把枪射出的三…