Matt Scudder, an ex-cop turned unlicensed private investigator, reluctantly agrees to help a heroin trafficker hunt down the men who brutally murdered his wife. When the PI learns that this is not the first time, nor will it be the last, that these men have committed this sort of twisted crime, he must blur the line between right and wrong as he races to track the deviants through the backstreets of New York City before they kill again.