Teri Garr has a gorgeous dignity. She's an infinitely rechargeable source of incandescence. In tonight's CBS movie "Intimate Strangers," at 9 on Channel 9, she plays an idealistic Army nurse who disappears in Saigon on the night of the great 1975 American evacuation, then shows up 10 years later in the States, much to the shock of her husband and his new-found girlfriend.

When Garr gets off the plane in an early scene, scruffed and buffeted and wearing eastern togs, and with a little Vietnamese boy in tow, she looks like Luise Rainer during a moment of trial in "The Good Earth." Writer Norman McLeod Morrill's script, meanwhile, serious though it is, borrows its basic premise from a classic Irene Dunne movie comedy, "My Favorite Wife," about a supposedly dead spouse who shows up to make mincemeat of her husband's marriage plans.

The point, or perhaps the bottom line, is, Teri Garr can be Luise Rainer and Irene Dunne combined, and more, and with a wistful and unmistakably contemporary spark all her own.

Writer Morrill isn't much concerned with sparks between the recently arrived wife and the startled mistress. This business is dispatched with swift civility. More of the friction centers on a spiritual gap that separates the husband and wife. He is now partnered in a lucrative private practice ("I treat tennis elbow, crabs and sunburn") and zooms around a cozy Florida town in a cushy Porsche. Her mind-set is still that of the secular missionary, the healer, the role she played with her husband at the military hospital where they both served during the war.

This is the pivotal conflict of the film, and for a while, it looks as if Morrill will resolve it in an inventive, realistic way; the wife begins to see a therapist, played by ace sensitive guy Max Gail, and you think that she will see in him a reincarnation of the man who inadvertently left her behind in Vietnam. But no. The way it all winds up is much more pat and much less convincing than that, or a number of other alternative endings, might have been.

Another weak link is Stacy Keach as the husband. He seems to be playing a piece of furniture. There's no discernible shift in character from the Vietnam surgeon to the Florida GP; Keach looks as though he is not interested in what's going on in this fellow's mind, so he lets the dialogue and the exposition do all the characterization for him.

But then, this is Garr's film, and she is quite an event. The confusions and the nightmares buzz around in her head and come out with convincing clarity, even if the dialogue is sometimes inadequate (would a woman who has spent 10 years in solitary really say she needs "some time by myself"?). When Diane Keaton, another actress known mainly for comedy roles, commences to suffer and swoon on the screen, a viewer may still feel a guilty urge to giggle, but Garr's range really seems broader. When she commences to suffer, you commence to suffer.

Here and there she seems to be holding back. Perhaps she felt uncertain in unfamiliar, for her, dramatic terrain. Or perhaps the director, Robert Ellis Miller, put the brakes on when he needn't have. On the other hand, Miller is able to maintain a compelling momentum even when the script appears to be losing its bearings (Morrill does try to touch one or two bases too many, though he mercifully stays away from the Vietnam guilt blues). And, get this, Miller even elicits a darn fine performance from Cathy Lee Crosby, as the suddenly supplanted Other Woman with whom the doctor had been cavorting.

Crosby has a muted confrontational scene with Garr that is an absolute beauty. Miller always gets the most out of Big Moments, like the airport reunion in the first act, but he also brings in all the other little tangential payoffs along the way. Nothing failed him here but the script's fade-out cop-out and a preoccupied Keach, whom Miller unforgettably directed in his film debut, "The Heart Is a Lonely Hunter."

It's Garr's turn to be unforgettable now, and she seems to be getting better and better at that.