穆尼是一个笨拙、肥胖、心胸狭窄在,且脾气很坏的警察,他有爱上了一个名叫克里斯托的女子。斯通(丹泽尔·华盛顿 饰)是克里斯托的辩护律师。穆尼憎恨斯通又被心脏病折磨。而斯通死于车祸时,情况完全逆转,斯通的心脏移植入穆尼的体内,更要命的是斯通的鬼魂竟然老是出没于穆尼身边,告诉自己是如何被毒贩首领杀害的,而他们已将魔爪伸向克里斯托。斯通发誓他将缠着穆尼不放,直到解决凶手为止,这下可要了穆尼的命……Jack Moony, a white cop, has it in for a black lawyer to the drug crowd, Napoleon Stone. That Stone is now dating his ex-girlfriend doesn't help matters at all. Stone is shot after Moony suffers a heart attack and wakes to find that he not only has a new heart, but that it is Stone's and that Stone's ghost is now his constant companion. Stone is insistent that Moony not only take care of his heart now but that Moony solve his murder.