Detective Perry (Russell), a corrupt veteran cop, and rookie Keough (Speedman) patrol L.A. streets as if they were in the wild west a hundred and fifty years ago. Perry tough; the younger Keough can't stomach what his partner asks him to do. Meanwhile, the cops' superior officers are at odds; one is a reprobate, and the other vows to stop him. Head cop Jack Van Meter (Gleeson), protecting a ruthless pair of snitches who murdered four people in a hold-up, orders Perry and Keough to frame and kill two sex criminals for the crime, giving rookie Keough has another chance to kill a perpetrator.

Set just after the April, 1992, verdict in the Rodney King beating case, when the LAPD let looters and arsonists run rampant, "Dark Blue" is well-acted, has believable details, and finds a compelling way of saying something meaningful. It's not mere formula cop-film. Novelist James Ellroy knows Los Angeles well, but has only recently succeeded in getting the story onto film; it was originally set during the 1960s' Watts Riots. However, the more-recent issue offers a better setting for a police department forced to reform.

It all works, even with almost too much else going on. Perry's wife Sally (Davidovich) complains he no longer has time for her: "You care more about people you hate." Keough is dating a young woman (Michele) who won't tell him her last name. Deputy Chief Arthur Holland (Rhames), a good cop, knows Van Meter is bad; just offered the job of Cleveland police chief, Holland must decide whether or not to stay and bring Van Meter down. Meanwhile, the hour is fast approaching when the LAPD will be exonerated of videotaped evidence of cops beating Rodney King; the police academy has scheduled a promotion ceremony for the same hour.

Ayer's screenplay and believable dialogue make the story's familiar pathway fresh. Shelton persuades the viewer to believe events will be cliche, but we're genuinely surprised at every turn. Perry's self-loathing evolves as he comprehends his role on the force. As he watches L.A. burn, we realize we've been brought willingly to this point, especially by Russell, whose acting reaches new depths.

The profound visceral impact, as characters drive through riot-torn Los Angeles, and we hear savage irony in Russell's lines, indict the LAPD just when it's exonerated, but good movies offer outcomes history should have reached.