查理（金•凯瑞 饰）是一名善良的巡警，他的妻子与别人偷情生下三个儿子后与情人私奔了。可是查理仍把三个儿子视为己出，儿子们也十分尊敬这个老爸。镇上的人们都欺负查理的善良，终于隐藏在查理体内的另一个狠角色——阿庆出现了。阿庆与查理截然不同，他到处捣乱，到处生事。 　　警方为查理检查，发现他患上了精神分裂，需要用药物治疗。这时查理要护送美女伊莲（芮妮•齐薇格 饰）回去纽约，可是伊莲的前老板狄克所做的不法事情被举报了，他认为举报者就是伊莲，于是狄克买通了警察等人，誓要杀死伊莲。 　　伊莲求助与查理，于是两人还有阿庆一起开展了一段亡命之旅。查理的药却丢在了旅馆里，于是一路上查理与阿庆毫无预兆的更换着，更复杂的是查理与阿庆都爱上了伊莲，查理与阿庆争风吃醋，争斗不断。而警察与狄克一直穷追不舍查理他们……Charlie is a Rhode Island state trooper with a multiple personalities. He is otherwise mild-mannered and non confrontational until somebody or something pushes him a little too far. That's when his maniacal alter-ego, Hank, takes over. Charlie is assigned on a routine mission to return alleged fugitive Irene back to upstate New York, but they wind up on the run from corrupt police officers. And their escape would be a lot simpler on everybody involved if Hank didn't keep stepping in at the most inopportune times....