It’s sometimes poetic. It’s sometimes haunting. It’s consistently, well, long.

A hard sell, ’tis, this Portia Coughlin.

Marina Carr 's allusive, surreal, and ultimately turgid play gets its D.C. premiere in a confused and confusing production by Solas Nua, the great theater company dedicated to works by living Irish dramatists. The show certainly doesn’t lack for ambition, but it’s somehow both overcooked and undernourished, boasting several fine performances but ultimately sunk by a muddled narrative, tentative staging, and a lethargic pace. The program says the show runs 90 minutes; Solas Nua’s web site ups the ante to 105. But even allowing for the intermission, the press-night performance ran to two full hours. And perhaps because the show’s climax — its narrative climax anyway, if not its thematic one — comes in the very first scene of Act Two, you. Feel. Every. Minute.

According to Solas Nua’s Dan Brick, the press night performance was the cast’s first crack at the show in front of an audience, so it’s possible director Jessica Burgess, whose work is often excellent, has since gone back and tweaked the tempo. But even if it were half as long, Portia Coughlin would still be a funeral dirge, by Carr’s design. The show is nothing if not a meditation on misery, loss, and doom. Example: What does a coffin smell like? “A cross between honeysuckle and new-morn putrification.” This from the lips of Blaize Scully (Rusty Clauss), the aged and cruel matriarch of the cursed Scully clan.

Clauss, and indeed, all of the actors representing the elder generation here, those whose destinies have already been fixed in stone (though the show argues that that’s all of us) are the best thing about the production. The Hooker with the Heart of Gold may be as stock as stock types come, but Charlotte Akin is still tender and moving in the role of Maggie May Dorley. As Portia’s beleaguered parents, Declan Cashman and Bryan Cassidy fight the good fight. Among the under-40 set, Grady Weatherford and Solas Nua regular Stephanie Roswell (as Stacia, a woman who changes the color of her eyepatch to suit the occasion) are fun to watch even when they’re given very little to do.

Which brings us to Portia. Portia, Portia, Portia.

As played by Solas Nua Artistic Director Linda Murray, she’s a self-destructive husk of a woman; indifferent to her devoted husband, neglectful of the children she never wanted, and somehow catnip to every swingin’ dick in the Irish Midlands. Whatever quality it is within her that inspires so many suitors — indeed whatever quality it is that spurs every other character to talk about her incessantly — Murray’s performance omits it. Why are all these people obsessed with Portia, a character who speaks only when spoken to, never smiles, does nothing? The enigmatic type can be very attractive, but Murray puts Portia’s misery right out there in the open, all the time. She isn't mysterious — she's just a drag.

We meet Portia on her 30th birthday. The milestone indicates she’s now been mourning her twin brother Gabriel, a singer “with a voice like God himself” who walked into the Belmont River, a decade-and-a-half previous, for exactly half her life on Earth. Camille Loomis plays Gabriel as an androgynous Raggedy Ann, either a stage-stalking apparition, or a weapon of Portia’s subconscious, or a bellweather of her slow descent into madness. Loomis is strong in this non-speaking role. Several dream sequences (?) show us Gabriel and Portia dancing silently together, eloquently making the point that for Portia, it’s all been pretty much downhill since she and Gabe shared a womb.

With its invocation of the myth of Castor and Pollux mixed in with the Emerald Isle’s homegrown strain of alcoholic woe, plus the appropriation of a few Ibsen-style Horrible Family Secrets for good measure, Portia Coughlin feels like Carr set out to write the most depressing, fatalistic play possible. There can be beauty in desolation, of course, but most of Burgess’ aesthetic flourishes — having the entire cast shuffle awkwardly onstage and interact with sheets of clear plastic hung from the ceiling, for example — come at the expense of clarity. The inner landscape of Portia’s damaged mind (if indeed that’s what we’re seeing) is nowhere near beautiful enough to pay for the long passages when we simply don't track what the hell is going on.

Worse is the fact that there’s precious little at stake in this thing. Portia, we're told, has spent every day since Gabriel's death at the bank of the Belmont River. Burgess riffs on Portia's aquatic obsession through an aquamarine lighting palette, a lot of rushing-water sound effects that will have many viewers contemplating the tantalizing nearness of the lavatory, and — most notably — the absence of any water onstage. In its many drinking scenes, the glasses are empty. This device, coupled with a gee-whiz technical indulgence at the end of the show that feels out-of-place in this otherwise low-fi production, is clearly meant to symbolize something, but it’s never clear just what.

And so goes the show. Despite the hard and honest labors of all involved, it ultimately amounts to little more than “Life’s a bitch, and then you’re reunited with your crazy twin.” Long before it's over, you want to grab Portia by her bony shoulders and tell her: "It's been 15 years. All these other people still love you. So get over it, Lady!"

Portia Coughlin (about two hours, 20 minutes including one intermission) is at the H Street Playhouse through April 6. Tickets are available here.