Annapurna seems to be having its moment – in an unusual coincidence, the first Philadelphia and New York productions of Sharr White’s play opened within days of each other.

Off-Broadway, the cast of this two-hander is a highly recognizable pair of television stars (Nick Offerman and Megan Mullaly).  But I don’t think it’s only local boosterism talking when I say that here at Theatre Exile, Joe Canuso’s sensitive direction, superbly detailed design by Thom Weaver, and the optimally intimate performance space, all make about as compelling a case for Annapurna as you’re likely to find.

And the two excellent Philadelphia actors – Pearce Bunting and Catharine Slusar?  Also, pretty much ideal.

In part, that’s precisely because Slusar and Bunting’s lack of celebrity is an asset here.  There’s nothing glamorous or even exceptional about Ulysses and Emma, the middle-aged couple in Annapurna, who find themselves reunited in a tiny Colorado town, in Ulysses’ squalid mobile home.  Once upon a time, the two were married, and they had a son, Sam.  But 20 years ago, Emma suddenly and quietly took him and drove away, without looking back – till now.  When she suddenly shows up again, it’s a complete surprise.

The reasons behind Emma’s departure and return are what Annapurna is all about.  It’s a story with several twists and turns – for the audience as well as the playwright.  Most of them are deliberate, and part of what keeps us hooked is the unexpected, gradually unfolding story.  White has a knack for slowly revealing crucial bits of the story.

At the same time, there’s a bumpiness to the tone that I don’t think is intentional.  I don’t mind saying that my heart nearly sank in the first five minutes, when a series of short, punchy scenelets suggest an unpromisingly broad comic restyling of Sam Shepard (imagine Fool for Love  as a quirky indie comedy for Jennifer Aniston and Bill Murray, and you’ll get the idea).  Those first few minutes also are among the few missteps for Canuso and his actors, who are too loud (it’s a tiny space) and too conspicuously working for laughs.

Fortunately, it doesn’t take long for the play (and this production) to find its footing.  Annapurna is no comedy – though there’s humor throughout, the underlying nature of the story is serious.  Slusar and Bunting are at their best when they are also at their quietest.  It’s then that you see how marvelous she can be when she’s listening, or simply recounting a story that seems innocuous, but clearly has a subtext.  Her very ordinariness is, in the theater, something extraordinary.

Bunting has the more difficult role – one moment, he needs to be larger-than-life, the next vulnerable – and he skillfully manages the transitions.  To the credit of both actors (and their director), we absolutely believe these are real people – even when White’s script occasionally strains credibility.

As you can probably tell, I’m not wholly convinced by Annapurna.  White has some notable gifts for dialogue, but less for structure – the play meanders too for too long, and when the climax finally arrives, it’s rushed.  (I also doubt it comes as a surprise.)  The title refers to a mountain in Nepal; that, and the character name Ulysses, suggest some larger metaphoric layer that would be overreaching.

What White does really well are the little interactions that are the substance of his character’s lives.  Somewhere near the mid-point of Annapurna, there’s a scene where Emma makes a sandwich for Ulysses (she knows he’s no good at feeding himself).  For the next few minutes, the most mundane of tasks becomes a microcosm of their complicated relationship – her conflicted feelings of alienation and nurturing, his battle between pride and neediness.  It’s these moments (and there are a number of them) where Annapurna really shines.  God is in the details, as they say – and in the theater, the small stuff can sometimes be a really big thing.

Through May 11, Theatre Exile at Plays & Players, 1714 Delancy St., 215-218-4022, theatreexile.org