A Labor Day picnic worth checking out

“Picnic,’’ the 1955 movie starring William Holden and Kim Novak, is the great exception to this rule. It somehow manages to offer both the laughable excesses of a bad movie and the subtle, moving emotion of a good one. It’s also, as far as I know, the only Labor Day movie ever made.

Labor Day is a no-frills holiday. No carols, no menorah, no presents, no colored eggs, no green beer, not even a traditional menu. But in its own quiet way, it marks the deep solemn turn of the year: the end of summer, the end of warmth, the end of vacation, the time when we need to stop our drowsy summer dreaming and put on real shoes and get serious. The party’s about to be over, if there ever was a party.

That sweltering, melancholy, restless itch to live, damn it, before it’s too late, is the underlying emotion in “Picnic.’’ Most of the action takes place at a Labor Day picnic in a poky Kansas town - the kind of picnic that has three-legged races, pie-eating contests, the crowning of a beauty queen, and music by a group called Ernie Higgins and His Happiness Boys.

It’s all incredibly comfy and wholesome, except that of course it isn’t. Beneath the superficial jollity, people are roiling with unruly emotions. Sexual frustration and self-loathing. Anxiety and snobbery. Jealousy. More jealousy.

The script can be melodramatic and clunky. (Count how many times Rosalind Russell refers to herself as “an old-maid schoolteacher.’’) But what makes the movie work is the genuine emotion brought to it by the actors, especially Holden and Novak.

He’s a drifter who’s just rolled into town. He has lived on his looks and is starting to lose them, but he’s all man. (In case you don’t get that he’s all man, he lifts heavy objects with ease and takes his shirt off. And in case you still don’t get it, the script calls for one woman to remark on the ease with which he lifts heavy objects, and for another to point out that he’s walking around without a shirt.)

She’s 19, the town beauty, good-hearted, a little dim, sleepwalking through the reverent attentions of the rich young man who could give her the country-club life her mother desperately wants her to want.

These two characters, at either end of the gorgeousness life cycle - his is reaching its expiration date, hers is just beginning - are clearly going to tangle, but the movie takes its time with them. They keep brushing past each other and saying “Hi’’ and then forgetting each other and moving on. The moment when they finally wake up and really see each other and dance, as the picnic nears its end, is one of the sexiest scenes ever filmed. No kissing, no dialogue, no nothing: just two grown-ups recognizing each other in a way that makes everyone else superfluous.

The next morning, everything has changed. The light is different. The wind is blowing. School’s open. People are wearing plaid. Things have gotten serious; decisions need to be made.

If you’re above a certain age - and I’m not even sure what age. Thirty? - you may be nodding in recognition. You remember when Labor Day was the time for the year to sober up and pull itself together. But if you’re young, you’re probably saying, “Huh?’’ You’re used to schools that start sometime in August, and summers that don’t feel all that summery because even if you do take your vacation then, you always have your cellphone with you.

Do yourself a favor. Rent “Picnic.’’ You can remember how things used to be, or learn how things used to be, before the year became one homogenized lump of productive time. You can laugh at the bad stuff. You can admire Novak’s lush, wistful beauty and Holden’s tattered magnetism.

And, if you wait until next weekend to watch it, you can make the summer last a little longer.

Joan Wickersham, a guest columnist, is the author of “The Suicide Index,’’ a finalist for the 2008 National Book Award.