Whatever its troubles, Bathsheba Doran’s new play, “Living Room in Africa,” does try to open a very interesting can of worms. In fact, it opens multiple cans of really squirmy, troublesome worms, all while pretending to be a portrait of a marriage in trouble. The play largely consists of broaching important topics – the legacy of colonialism in Africa, the point of modern art, what to do about AIDS. But despite doing so in an adventurous way, “Living Room” only winds up looking ungainly for its trouble.

A British couple in their 30s, Marie (Ana Reeder) and Edward (Rob Campbell), have just moved to an unnamed country in southeast Africa. Edward, backed by an international consortium, has come to build an art gallery and Marie is the tag-along who will use the time to write. Before our eyes have time to adjust to the dark, we have learned that the marriage is sexless, Marie suffered once long ago from depression, and the two of them are negotiating a healthy amount of white liberal guilt. When Marie’s brother Mark (Michael Chernus) gives her guff for having a black cook, the couple has a refrain. “What could we do? They’re all black here!” they whisper, before topping up each other’s colonially appropriate gin-and-tonics.

Another mantra, “What can I do for you?” has awful consequences in Africa. The white visitors say it easily, always with the limits of their generosity firmly in mind. They seem surprised when others actually take them up on the help they offer, and are forever exposing themselves as terrible incompetents. Marie can barely peel a potato; Edward uselessly writes a local a check, far from any bank that would cash it. Still, each of them makes an African friend whom they must choose to help or abandon. A builder working on the gallery, Anthony (Maduka Steady), believes that Edward will actually take him out of the country, and Marie, becoming more aware of the suffering around her, takes in their HIV-positive cook, Nsugo (Marsha Stephanie Blake), and her sick, dying children.

Ms. Doran writes the piece as a dark take on drawing room comedy: All the action takes place in a Marie and Edward’s living room in a series of uneasy social evenings. Set designer David Korins does a magnificent job of placing them in a prairie-style bungalow that seems completely un-African. It’s a gorgeous metaphor for Western answers to African problems – it simply ignores what would be locally appropriate. And where Ms. Doran hammers at a point, Mr. Korins makes it gently: Instead of having a character screech, “But it’s all our fault!” while addressing the legacy of colonialism, Mr. Korins simply leaves dark spaces on the walls where an earlier occupant’s pictures once hung.

Still, Ms. Doran’s occasional hops onto the soapbox wouldn’t be so troubling if the central relationship made more of an impact. Mr. Campbell has a gorgeous elusiveness about him, and I kept waiting for him to reveal some astonishing secret. But Ms. Reeder’s character, unfortunately, gets the lion’s share of the storyline, and she has a whining delivery that makes her an interestingly unsympathetic stage presence. But all moral crusaders can’t be dewy like Rachel Weisz in “The Constant Gardener”; sometimes they are irritating drama queens like Marie.

But director Carolyn Cantor doesn’t plumb any realistic depths in Marie or Edward, and their relationship stays just as flat. Their moments alone together onstage sag terribly; it’s only when someone else shows up – like the brother Mark, or their late-appearing American landlord, Michael Lee (Guy Boyd) – that the play begins to move.

When the company bows, Messrs. Chernus and Boyd stand at either end, anchoring the line. Both of them are big men – though Mr. Chernus looks small in comparison to Mr. Boyd’s only-suspenders-can-tame-it belly. It’s appropriate, actually, because these performers exercise an outsize influence on the play. Both of them have massively likable stage personae, and each of them can cut through Edward and Marie’s miasma of self-obsession. In fact, in the third act, cheerful, zebra-eating Michael Lee seems so much more interesting than the droning couple, he must be hidden in kitchens so as not to steal the show.

Still, despite a certain sense of claustrophobia, accentuated by Eric Shim’s nearly silent sound design, this “Living Room” isn’t a bad place to spend two hours. Just like Marie, Ms. Doran has some trouble with the execution, but drawing our attention to the African AIDS humanitarian crisis is a worthy mission. And so if Ms. Doran’s piece uses a bludgeon when it could have used an epee, does it really matter how she prods us into action?

Until April 15 (410 W. 42nd Street, between Ninth and Dyre Avenues, 212-279-4200).