Watching "Training Day," which as the title illustrates takes place during a single 24-hour period, reminded me of my first day of teaching in a New York City high school. Antoine Fuqua ("Bait," "The Replacement Killers") gives us one intense police dramas with the marvelous Denzel Washington's going increasingly over the top in the role of rogue detective Alonzo Harris. Though everything appears to hit the fan about a half hour into the picture, Fuqua calibrates the potent story of David Ayer ("The Fast and the Furious") so that we can overlook the lurid and contrivance-soaked conclusion and leave the theater with the feeling that maybe the cops who are good guys can really defeat the forces of iniquity.

The story starts off with a patient exposition showing us that perhaps Jake Hoyt (Ethan Hawke) is not choir-boy idealistic despite his conviction that drug pushers are the scum of L.A. and that he has a calling to rid his city of them. His wife had recently given birth, they're living in a cramped apartment, and he wants to be promoted to detective in order to move his family to a more capacious house. You can see Hoyt's opening-day tensions as he reluctantly drags himself out of bed, talks to his prospective mentor Alonzo on the phone peppering his answers with "sir," and sits dumfounded in the morning coffee-shop rendezvous with his new boss as Alonzo focuses on the newspaper and dresses down his new acolyte for speaking and ruining his concentration.

Yet Jake is in awe of the big man, all the more as he watches Alonzo traipse around his broad geographical precinct like a warlord ruling over his serfs. The expression "what a difference a day makes" hits home for young, ambitious and naive Jake as the song title has probably not quite succeeded in doing to anyone else with such furor. As Jake follows his boss' lead to some extent, using a choke hold on one of two pond scum people in an L.A. back alley who are in the processing of raping a fourteen-year-old girl, Alonzo himself ups the ante in dealing with some of the higher-ups in the drug trade, with corrupt apparatchiks in local government including a fierce, cigar-smoking D.A. (Harris Yulin), and in scaring the hell out of some college kids slumming by driving through the ghetto to buy marijuana.

As Alonzo hones in the worst of L.A. citizenry, I'd be curious to know what various denizens of the America theater audience. Would they cheer this direct, extra-legal action, a kind of the-end- justifies-the-means philosophy as they did while Charles Bronson's character in Michael Wiener's "Death Wish" did in offing muggers on the subway rather than bothering to arrest them and take his chances on justice before a jury? After all Denzel Washington is awfully persuasive as one of our finest actors, perfectly able to play the good guy as he did in as a coach in "Remember the Titans," as a South African activist, Steven Biko, in "Cry Freedom" and once more in a fiery supporting performance in "Glory." Though his role this time does not call for the complexity he demonstrated while the incarnation of Malcolm X in the film of that name, he does a smashing job in his most villainous role. Ethan Hawke, recently performing in the title role of the indecisive prince in Michael Almereyda's "Hamlet," pulls off a role not entirely dissimilar. Rather than refuse illegal orders of his new boss, such as the command that he smoke a crack pipe loaded with PCP and wash away the illusions with a few beers, he hesitates, then, thinking of the new house he will get down the road, he follows the directives.

There's an unfortunate tendency to end action-adventure pictures with extreme, Bonnie-and-Clyde violence. In Jonathan Mostow's "Breakdown," Red Barr (J.T. Walsh) is done in by having a truck thrown on him by Jeff Taylor (Kurt Russell) and more recently a bad guy is buried alive in "Don't Say a Word." A similar concluding scene threatens to destroy the quality of what went on before. But thanks to a stellar, riveting performance by Denzel Washington in a villainous role that so many actors would kill for and a remarkable show by Ethan Hawke as his bland foil, "Training Day" is an action police drama which is as good as a Hollywood genre pic can get.