"A Different Story" depends on the most familiar of stories: Boy meets girl, boy and girl fall in love, boy and girl marry, boy and girl teeter on the brink of divorce, boy and girl reconcile. The gimmick calculated to give this conventional progression a semblance of topical significance is obviously contrived: Boy and girl are identified as homosexual before circumstances throw them together and provoke a happy heterosexual consummation.

It's a trifling pretext, and the movie remains a trifle, evidently so lightly regarded by the distributor, Avco Embassy, the company that gave you "Rabbit Test," that it didn't even send a few stills to town. Nevertheless, it's a trifle with redeeming personality appeal and a genuinely affectionate temperament. As the supposedly disparate lovers, Perry King and Meg Foster make an overwhelmingly attractive and compatible couple, and their sexual rapport is enhanced by Paul Aaron's attentive, straightforward direction.

Although the plot is shoved along by introducing one stale contrivance after another, the performers convey a moment-by-moment emotional conviction. You may not believe in the reality of the characters as formulated by writer Henry Olek, but you believe in the suitability of King and Foster as a romantic match.

Even in the most foolish situations they act with admirable integrity. Sometimes performers who believe in each other and enjoy sympathetic direction can superimpose that mutual respect on superficial assignments. All the false notes are in the script. Working from this dissonant score, King and Foster manage to play an agreeable duet.

King is supposed to be a Belgian emigre name Albert who enters the country as the latest playmate of a fickle orchestra conductor played by Peter Donat. Quickly discarded by his patron upon arriving in Los Angeles, Albert finds shelter when the patron's realtor, Foster as an apparent lesbian named Stella, takes pity on him and puts him up.

An exceptional cook and housekeeper, Albert makes himself domestically ingratiating to Stella and gratuitously useful to author Olek as a source of predictable gags about role reversal. When the conductor shows renewed interest in Albert and sics the immigration authorities on him when he resists, Stella decides to save the day by marrying Albert, thereby transforming him from illegal alien to American citizen.

The arrangement continues as before, Stella rushing off to the office to sell property and Albert keeping house, until the newlyweds return in drunken high spirits from a party, get silly in the bedroom and find that they satisfy each other. The adjustment to this revelation ought to be enough to last one inordinately contrived romantic comedy, especially since Stella has a neurotic ex-girlfriend, played with a stunning mixture of goofiness and pathos by Valerie Curtin, who needs to be handled with tender loving tact.

As a matter of fact, the complications proliferate: Albert and Stella have a baby, he becomes the bread-winner and threatens to wreck the marriage through careerism and philandering, she catches him cavorting in the shower with another woman, etc., etc.

Throughout all this expository tangle King and Foster maintain a performing integrity that keeps them on a higher plane than the material. They harmonize as pleasantly as Robert Redford and Jane Fonda in "Barefoot in the Park" or George Peppard and Audrey Hepburn in "Breakfast at Tiffany's."

Despite the fabricated obstacles, they make Albert and Stella look right for each other. They hit it off. That elusive romantic chemistry is apparent when they interact.

They even look humorously compatible: The handsome horizontal lines in Foster's face somehow lock in with the handsome vertical lines in King's. They match both formally and temperamentally, unlike the current historic mismatch in "Grease," where Olivia Newton-John and John Travolta suggest an indigestible cross of One from Column Bland with One from Column Spicy.

In a curious act of overreaction, the Gay Activists Alliance has issued what it calls a "media alert" against "A Different Story," accusing the movie of "a vile attempt to condemn real gays to limbo. It seems to say . . . its two gay characters cannot love and live happily ever after with a member of their own sex; they must try to live a heterosexual lifestyle with each other."

Of course, the fundamental subterfuge is the idea that these characters are homosexual in the first place. There's never any compelling reason to believe it, outside of the need to get the story started. Confirmed homosexuals might be justified in taking offense at the artificiality of the premise, but neither the performers nor the director makes a move that could be honestly interpreted as hostile to or disdainful of homosexuals. King and Foster succeed so well in individualizing these contrived characters that one's foremost thought is how satisfying that they found each other, rather than how satisfying that they went straight.

It's possible that this slight movie has exposed a chink in the gay activist armor. Could the make-believe romance of Albert and Stella seem a threat, objectifying the fear that one's partner might be enticed into (or back into) the heterosexual majority? It's only a speculation, but it seems slightly hysterical to ascribe vile motives to such a pleasant little obscurity of a movie.