A man (VAL KILMER) sits in a burning room playing a trumpet, seemingly unaware of or completely at ease with the danger he's in. He may be Danny Parker or Tom Van Allen, but he isn't sure, and so he invites us to decide while taking us on a trip leading up to this point.
We first see Danny as a "tweaker," one of many men including Jimmy The Finn (PETER SARSGAARD) and Kujo (ADAM GOLDBERG) who are users and addicts of crystal methamphetamine. Yet, things aren't what they initially seem. It turns out that Danny is an informant to L.A. narcotics agents Morgan (DOUG HUTCHISON) and Garcetti (ANTHONY LaPAGLIA), who use his tips to bust drug rings. They're currently interested in his dealings with Bubba (B. D. WONG), an Asian man dressed somewhat like a cowboy.
With the help of Jimmy, Danny then arranges to meet Pooh-Bear (VINCENT D'ONOFRIO), a notorious and deranged dealer who did so much "gack" that his real nose had to be cut off. As his henchman, Big Bill (JOSH TODD) and Little Bill (DANNY TREJO), keep an eye on him, Danny arranges a large drug buy for Bubba through Pooh-Bear.
As all of this occurs, Danny must deal with a mysterious car that keeps following him, knowledge that his neighbor, Colette (DEBORAH KARA UNGER), is being abused by her violent and ill-tempered boyfriend, Quincy (LUIS GUZMAN), as well as conflicting memories of his past life as Tom Van Allen, a trumpeter with a beautiful wife, Liz (CHANDRA WEST).
As things continue to play out, we repeatedly learn that things aren't what they initially seem and then watch as Danny attempts to complete an elaborate plan of revenge against those he believes have wronged him.