"The Big Easy," starring Ellen Barkin and Dennis Quaid, is the sexiest, most companionable movie of the summer. Set in New Orleans, it's an amiable, loping, goof of a movie, with charm to burn and not a thought in its head.

This is one movie that lives up to its billing; it's easy all right. Like falling off a log. If you've ever listened to a recording by the great New Orleans blues pianist Professor Longhair, whose music, along with that of Beausoleil, Buckwheat Zydeco and the Neville Brothers, is featured on the sound track, then you'll be familiar with the film's infectious, gootchie rhythms. This movie rocks, but not full out. It keeps up a brisk, jogging pace, but there's always enough time for a another drink, a bit of business, a flirt.

The movie's pleasures aren't those of plot or characterization (though the performances by the stars and the supporting cast are springy and full bodied). In "The Big Easy," style is everything, and, for a film set in New Orleans, that seems perfectly appropriate.

The director, Jim McBride, hasn't so much filmed his script (which was written by Daniel Petrie Jr.) as pumped it full of bubbles. If keeping the details straight is your measure for a storyteller, then McBride isn't particularly gifted, but then again the story isn't much worth telling anyway. Conceived as a thriller about crooked cops, drug peddling and murdered wise guys, it's an eminently disposable, routine cop yarn. Remy (Dennis Quaid) is a cop from a long line of cops and, like his father before him, he's on the take. This in no way makes him special: Everybody in New Orleans is on the take. It's a tradition, the way things are done.

But there's someone new in town who's threatening to blow the gravy train off its tracks. Business, Big Easy style -- the Big Easy is what the locals call New Orleans -- isn't acceptable to Anne Osborne (Ellen Barkin), the new assistant district attorney assigned to investigate the corruption within the department. Anne is arrow-straight, the type who figures out the tip on checks down to the penny. (As the movie euphemistically puts it, she's from "out of town.")

Of particular interest to her are a number of recent Mafia hits. Anne believes that cops may be involved and pays Remy a visit to check out the situation. Though of course he can't show it, from the moment Remy first sees Anne sitting in his office, he's a goner. Watching her surreptitiously as she scratches a spot behind her ear with the eraser of her pencil, he says, "Great neck," and the movie is off and running. The main ingredient in this picture, and the main reason why it has such a pleasing, ingratiating spirit, is the chemistry between these two. In terms of sheer pleasure, I can't think of two actors I'd rather watch than Barkin and Quaid, and though both have had better material to work with, neither has had as much of an opportunity to shine.

You rarely see actors on screen who look as if they're having as much fun as these performers seem to be. And there's no reason why they shouldn't be; they complement each other beautifully. Their scenes together are like episodes in a courtship -- even the ones where Quaid is on trial for taking a bribe, with Barkin as the prosecutor. They partner each other like dancers, each showing the other off. (And when they actually dance a jukey waltz together, it's bliss.) The central contrivance in the movie is the clash of temperaments between the easygoing Remy and this starchy DA. And I call it a contrivance because you never for a moment believe that this conflict is going to wind up anywhere other than where it does -- in bed.

Their love scene is the key pas de deux, and it sets the tone for everything that follows. This may not be the hottest scene ever filmed (and even though the couple remain nearly fully clothed and their passion unconsummated, it's still pretty hot), but it's certainly one of the smartest. The sex here doesn't come off as hyped up or porny. Instead it's slinky and natural, and what makes it so rare is that the participants actually seem to know what makes sex so much fun. (Sample dialogue: "Would you stop that please?" "What would you like me to stop? That? Or that?") The sequence isn't wasted in terms of characterization, either. And what you see of them at that moment, with their masks down, colors your impressions for the rest of the film.

The movie is really about styles of behavior, and it shows how people choose styles that disguise as much as they reveal. From looking at him, Remy seems every inch the master of silky expediency, and that's how Quaid plays him -- as a self-aggrandizing, smooth-talking jerk. But at the same time, Quaid shows how Remy's good-natured suavity is a tactic to make people think he's dumber and more corrupt than he actually is in order to get the drop on them. But style is more than a mask; it's self-deception, too, and the little ways Remy has cheated -- the payoffs from the so-called "Widows and Orphans Fund," the free dinners and the occasional favor -- have taken more of a toll than he realizes.

That's where Anne comes in. She questions his methods (which are borderline unconstitutional) and his ethics (borderline nonexistent), and in doing so makes him confront what he's become. At one point she says, "Face it, Remy, you're not one of the good guys anymore," and it's like a slap upside the head. As far as audience pleasure goes, having Anne let a little air out of Remy's good-time balloon is a danger.

The risk you run is that of making Anne look too prim and rigid. But Barkin navigates these shoals beautifully. And she does it by turning Anne's uptightness into a klutzy joke. It's a laugh in itself to cast Barkin as a prig, and that the role is not a snug fit for her makes her work here all the more appealing.

There's tremendous skill in the way Barkin walks the line between "playing" and "playing with" her character. She has one of the most naturally plaintive faces in movies. Watching her on screen, in "Diner" and "Tender Mercies" and "Buckaroo Banzai," I've never for a moment felt that there wasn't something vividly alive in it. But what Barkin shows here are her skills as a comedian. Restricted previously to smaller, supporting roles, Barkin has registered, magnificently, as an actress; here, she registers as a star.

The same is true for Quaid. A gator grin spreading over his face, Quaid is so unabashedly full of himself that you get swept up in his enthusiastic high spirits. He's a life-giver, like Nicholson. When, at one point, Anne asks him, "Aren't you ever scared?" he answers, "Who, me? Why bullets bounce off me, sugar." And you believe him.

The New Orleans setting is essential to the film's freewheeling mood, and McBride has a sure feel for the place. But for the most part he's smart enough to stand back and turn things over to his actors. In addition to the stars, there are some crafty, attention-grabbing performances given by supporting players. Lisa Jane Persky and John Goodman have a couple of good scenes as Quaid's sidekicks. And, as Remy's mom, Grace Zabriskie has a wonderful bayou elegance. But the real standout bit of flamboyant, eye-rolling nonsense is delivered by the late stage actor Charles Ludlam. He plays the defense attorney representing Remy, and his line, "New Orleans is a marvelous environment for coincidence," delivered with an outrageous Big Daddy drawl, is the best in the movie.

Ludlam's mugging performance could stand as a symbol for why this movie is so much fun: His sendup makes explicit everything that's implied in the other performances. "The Big Easy" is a ramshackle affair whose shambling style gets inside you. This movie has bedroom eyes; it's great company. And together Barkin and Quaid pull off something that not many movie couples do: They make you ache to see things work out between them. That's why the ending, tacked on as it is, is so enormously satisfying. You want them back in that bedroom again, giggling like happy idiots, enjoying the Big Easy.

The Big Easy, at area theaters, is rated R and contains some violent and suggestive material.