Imagine Dirty Harry with a bad coke habit, played by Nicolas Cage in New Orleans. Cage gives us an outstanding performance as someone who goes though those violent coke induced mood swings. The iguana which appears in the movie from time to time is symbolic of the metaphor "monkey on the back." Cage is investigating a brutal family execution and interweaves his personal failings into the process. His girlfriend is a prostitute who he protects and supplies drugs. He has a gambling habit, and owes money (bets too much on LSU) and of course steals from the evidence locker.
He also shakes down people for information, even grandmothers. Makes Dirty Harry look like a sissy. Lots of drug use, bad language, sexual situations, and some violence.
Good story. Plot fairly simple to follow. The movie, at time, has the feel of a dark comedy.