This movie depicts the authentic story of the hunt for the dangerous criminal Emile Buisson, who escaped from prison in 1947. During three years Buisson manages to hide from detective Borniche by repeatedly killing his informants. When he's finally caught with help from the little criminal Paul, Buisson will have committed more than 100 robberies and killed 30 people. 本片根据法国警官追辑战后法国头号国家公敌杀人犯的史实改编，描述了他追捕从精神病院逃脱的凶手毕松的故事。毕松是个极端危险的犯罪分子，已经被警方通缉。他从监狱逃脱后的三年间，通过不断杀害联系人来逃避警方的追捕，最后却终于落网。
