故事发生在新奥尔良市,布莱基因(杰克·帕兰斯 Jack Palance 饰)是一个不学无术游手好闲的小混混,他和一个名叫查卡的非法移民之间产生了一些经济纠纷,于是便找来了好友,将查卡杀死了。查卡的尸体被发现后,被送往公共卫生局进行解剖,负责解剖的克林特医生(理查德·威德马克 Richard Widmark 饰)震惊的发现,查卡患有会传染的瘟疫,这也就意味着,凡是和查卡接触过的人,都有患病的可能。 为了避免瘟疫大肆传播的惨剧发生,克林特医生奉命在四十八小时内要找到所有查卡生前接触过的人,并且这一调查必须秘密的进行,否则将会引起恐慌。When a body is found in the New Orleans docks, it's pretty obvious that he died from gun shot wounds. The police surgeon notices that the man is also displaying other symptoms and Lt. Commander Clint Reed, a doctor with the U.S. Public Health Service, diagnoses a highly contagious disease, pneumonic plague. He tries to convince local officials to find everyone who may have been in contact with the dead man. The Mayor supports his efforts but many, including the police, are doubtful. Reed wants to avoid publicity so as not to panic the public. They have little information to go on - they don't know the dead man's identity - and Reed estimates they have 48 hours before disease begins to spread. With police Capt. Tom Warren going through the motions, Reed sets out to find the killers.