哈里(克林特·伊斯特伍德 Clint Eastwood 饰)是美国旧金山的一名资深警察,警局总是把一些难以解决的案件抛给他,而他为了破案也不惜使用一些非法的手段,因此他得到了一个绰号——“肮脏的哈里”。 旧金山出现了一个无差别射杀魔,在第一个受害者遇难的同时,凶手留下了一封恐吓信,要求获得10万美元的现金,否则,每过2小时,他将射杀一个市民。随着受害者的增加,无能的政府决定向凶手妥协,但哈里不能接受这样的妥协,他擅自行动逮捕了凶手,却也导致了人质的死亡。令他意想不到的是,好不容易捉拿归案的凶手,竟然因为精神方面的疾病逃脱了法网,之后变本加厉劫持了一辆载满儿童的校车。这次,愤怒的哈里再也不能忍耐了,他展开了同凶手的周旋,并在最后时刻射出了那颗代表着正义的子弹。In the year 1971, San Francisco faces the terror of a maniac known as Scorpio- who snipes at innocent victims and demands ransom through notes left at the scene of the crime. Inspector Harry Callahan (known as Dirty Harry by his peers through his reputation handling of homicidal cases) is assigned to the case along with his newest partner Inspector Chico Gonzalez to track down Scorpio and stop him. Using humiliation and cat and mouse type of games against Callahan, Scorpio is put to the test with the cop with a dirty attitude.