After a history of drug abuse and prostitution, Munch Mancini now works as an automobile mechanic, work she loves and does so well that even her male co-workers acknowledge her skill, if somewhat grudgingly. She has a daughter, a little girl left in her care by a dying friend. And she is about to marry a police officer she loves deeply. It all comes crashing down when a friend in the police department calls to tell her that her fiancé is dead, shot down by his fellow cops in a drug bust gone wrong. Refusing to believe the explanation she is given, Munch goes on a dangerous mission, first for knowledge, and then for revenge.