Whatever headaches Richard Greenberg might be having, what with this month’s closing of “Breakfast at Tiffany’s” on Broadway and next month’s opening of “Far From Heaven” at Playwrights Horizons, he can relax about “The Assembled Parties.” The Manhattan Theater Club, with a.d. Lynne Meadow at the helm, has done a sweet job on his messy but moving domestic dramedy about a Jewish family living — and eating and arguing — over two decades in a 14-room rent-stabilized apartment on Manhattan’s Upper West Side.   

A 14-room rent-stabilized apartment on Central Park West? In this real estate-obsessed town, that’s as good as a castle on the Hudson — better, because it’s closer to Zabar’s — and Santo Loquasto has designed this treasure with all the shabby beauty and comforting warmth it deserves. In lighting this womb, Peter Kaczorowski takes care to cast a few shadows in the corners of the many rooms that glide smoothly in and out of sight on a revolve, while sheathing key characters, like those played by divinities Jessica Hecht and Judith Light, in golden halos. Costumer Jane Greenwood makes do with flattering period costumes, the kind with waistlines.

Julie is the hearth goddess in this play and as Hecht inhabits her, it is perfectly OK to worship at her feet. A former movie star, she’s still lovely and charming and downright embraceable, but also smart and funny and not afraid to say what she thinks — and means. “Touching, so touching, all of you,” she says, gushing about her son’s college graduation to a classmate of his who has come to spend Christmas. “So witty, so oblique, so over-educated, so utterly ignorant of absolutely everything.” (Her husband, Ben, is well observed by Jonathan Walker, but no mortal man could really deserve her.)

Julie is not only a wonderful character who repays the scribe’s obvious devotion, she also plays well with others, especially her outspoken sister-in-law, Faye. As Light attacks this nimble-minded, sharp-tongued neurotic — with wicked glee and pitiless honesty, delivered in the guise of a palace wit — she’s so perfect you’d think the part had been written for her. (And, it was.)

No wonder that a college friend of Scotty’s (Jake Silbermann), the young prince who lives in this castle, thinks he’s gone to heaven when he’s invited to spend Christmas in 1980 with this eccentric family. Jeff (the excellent Jeremy Shamos, playing on stages everywhere this season, and probably coming soon to one near you, too), is actually too sweet and innocent to be true, but come Act Two, he’s grown into that persona.

Since the family is Jewish, the physical trappings of this Christian-pagan holiday are discreet and mainly representational. But keep an eye on that tiny stump of a Christmas tree. When the scene is reset in Act Two for Christmas Day in 2000, it has grown to impressive height and somehow acquired an angel on top. The ironic comment is subtle but clear: the more this family falls apart, losing members, losing its religious beliefs and political foundations, sometimes even losing heart, the more it clings to old rituals like cooking holiday dinner and decorating the tree.

In broad terms, that’s pretty much what this bittersweet play is about — the loss of precious things over time and the struggle to hang on to what still matters. The family apartment, for sure, and the family bonds that all those old rituals and symbols represent.

As for the specifics … well, it’s hard to discuss the specifics of plot and theme and event when the scribe doesn’t pay them much mind. Greenberg chooses to work almost exclusively with character, language, and ephemeral abstractions. And although his talky, static style has done him in in the past, this time he was lucky.

This time he bought his way out of the slipshod construction and baggy plotting with two great characters. Julie and Faye are natural enemies but too fond of one another to declare war. Their warm relationship is the heart of the play, just as the wonderful rapport between Hecht and Light is the heart of this production. And in this case, hearts trump clubs.

The Assembled Parties

(Samuel J. Friedman Theater; 650 seats; $120 top) 

A Manhattan Theater Club presentation of a play in two acts by Richard Greenberg. Directed by Lynne Meadow.

Sets, Santo Loquasto; costumes, Jane Greenwood; lighting, Peter Kaczorowski; original music & sound, Tom Watson; hair & wigs, Tom Watson; production stage manager, Barclay Stiff. Opened April 17, 2013. Reviewed April 12. Running time: TWO HOURS, 25 MIN.

With: Jessica Hecht, Jeremy Shamos, Jonathan Walker, Mark Blum, Lauren Blumenfeld, Judith Light, Jake Silbermann,  Alex Dreier, Gabriel Sloyer.