At the outset of Frank McGuinness’ Someone Who’ll Watch Over Me, a Beirut prison’s cacophony gives way to Ella Fitzgerald’s version of the title tune as the lights reveal two men chained a few feet apart on a hard rock floor. The song is both a memory—the final selection in a personal version of “Desert Island Discs”—and a fervent prayer. These abandoned men, and a third who will soon join them, desperately need someone to watch over them, and McGuinness means to make drama of their attempt to find that someone in each other.

The playwright doesn’t entirely succeed, but Studio Theater’s handsome, heartfelt production certainly goes a long way toward vindicating his struggle. Sharply acted by its three principals and designed to a fare-thee-well, it creates a claustrophobic hothouse in which prison-born paranoia and insecurity blossom into the kind of collective strength that is humankind’s only real defense against despair.

McGuinness wrote the play after reading The Evil Cradling, Brian Keenan’s autobiographical account of his ordeal and that of fellow hostages Terry Waite and John McCarthy in Beirut. But the play’s characters are fictional creations—a stalwart African-American named Adam, a romantic Irishman named Edward, and a prissy English professor named Michael—who seem to have been conceived primarily as national stereotypes. Adam (Vincent Brown) has been imprisoned for about four months as the play begins and is intent on keeping his all-American physique intact through sit-ups, push-ups, and any other calisthenics the 5-foot chain attached to his ankle will allow. Edward (Neal Moran) takes the view that keeping spirits up is equally important, which is why he chatters on about “Desert Island Discs,” Irish soccer teams, his wife and kids, and anything else that will take the prisoners’ minds off their circumstances.

At first, when Michael (Alan Wade) is dumped in with them, he seems a too-pat authorial intrusion—a character whose presence will allow the others to supply exposition—but it quickly becomes clear he’s to have a more significant part in the proceedings. He and Edward are soon at odds over issues that sound as if they’re rooted in Anglo-Irish politics but keep resolving themselves in personal ways. Edward takes umbrage at having his accent referred to as a dialect; Michael assumes that every mention of family is an attack on his (and by extension England’s) virility. By the time someone mentions the potato famine, all hell’s ready to break loose.

Of course, the three men have only one another to lean on, and a common enemy in their unseen (to the audience at least) Lebanese captors. McGuinness intends for the situation itself to be the antagonist, not the men or political forces involved. None of the three prisoners has any connection to world politics, and the clearest picture the audience is ever given of their jailers is a reference Michael makes at one point to being “held captive by children.” It’s the men’s survival tactics McGuinness is interested in—the character-revealing games and diversions with which they stave off depression, and the ways they find of supporting each another. This ultimately puts the author in a bind, since all his characters can do is kill time until they’re dispatched to their widely disparate fates. As their actions have no impact on what happens to them, there really isn’t drama in a conventional sense—just narrative of an existential sort. Still, as the characters re-enact tennis games, imagine movies, compose the letters they’d write if only they had paper, and toast themselves with mock cocktails, they grow compelling enough to sustain the evening on their own.

In part that’s due to the subtly shaded performances director Jim Petosa has elicited from his actors. Brown makes vivid sense of the play’s underwritten African-American (who, in other productions of the play, has been described as existing only to be sacrificed after singing a spiritual). Wade’s delicate, soft-spoken Englishman is eloquently funny when he’s arguing etymology and heartrending when language finally fails him. Perhaps most appealing, though, is Moran’s robust, lyrical Irishman, who alternately coaxes the others to remember the world’s brightness and promise, and despairs at the solidity of the walls that hold it at bay.

Those walls are stunningly captured by James Kronzer’s claustrophobic setting, a rock floor backed by massive unyielding stone, surrounded by a moat of darkness and crushed from above by a monumental concrete slab with a barbed-wire opening that barely lets in lighting designer Daniel MacLean Wagner’s ever-changing twilight. Clad by costumer Helen Q. Huang only in filthy T-shirts and shorts, the actors slowly take on the color of their surroundings, absorbing their environment as it absorbs their strength of will, gradually turning to stone, but never giving up their humanity.

All I really remember about Source Theater’s late-’80s production of The Artificial Jungle is the sock ostentatiously stuffed down the front of its leading man’s pants. It reached nearly to his knee, explained why the leading lady and her husband kept leering in his direction, and pretty much summed up the coarseness with which Charles Ludlam’s spoof-noir was being handled.

I suspect what I’ll remember about Woolly Mammoth’s current production of the play—which crosses Double Indemnity with The Postman Always Rings Twice to arrive at Little Pet Shop of Horrors—is the wooden fish swimming in circles in their aquarium. It’s a considerably tamer image, and one that can also serve as a summary of the production since it nicely evokes the predicament of the evening’s actors. They look trapped. By intermission, so does the audience.

Ludlam and Woolly Mammoth would ordinarily seem a marriage made in heaven. The company’s sensibilities have everything to do with excess, which means they ought to be wonderfully in tune with dialogue on the order of “I didn’t get these lips from sucking on doorknobs.” That’s the come-on uttered by Roxanne Nurdiger (Becky Woodley swathed in animal-print lycra) when a moody drifter named Zach (Mitchell Patrick) shows up at her husband’s pet shop looking for work. Roxanne hungers for excitement while her husband Chester (Daniel De Raey) lives only for Thursday-night domino games with his mother (Steven Dawn in a variety of fright wigs) and the simpleminded local cop (Christopher Lane). Roxanne and Zach hatch a murder scheme involving a pillow, a ladder, and a tankful of piranhas, but in Ludlam’s world even the best-laid plans have a way of going awry. This one leaves its would-be lovers with a half-eaten corpse, a stroke-impaired mother-in-law, and a too-talkative parrot.

Goofy as this probably sounds in synopsis, it falls flat in Howard Shalwitz’s haphazardly frenetic staging. I can’t imagine that this savvy director encouraged his cast to approach The Artificial Jungle as straight melodrama, but that’s mostly how the evening plays. Only Woodley’s pouting, sultry Roxanne gets much comic mileage from the dialogue, while the rest of the cast tends to rely on physical business that rarely pays off. The production scrimps where it shouldn’t (the pet shop’s midshow junglification only adds a couple of vines to Lewis Folden’s purposefully tacky setting) and squanders the comic potential in everything from Dawn’s drag act to that center-stage piranha tank. As a result, the show starts to seem attenuated and a little desperate before even the first of its four scenes is over. When laughs didn’t come on opening night, the performances got increasingly strident until nearly everything was being shouted, proving mostly that while camp is often noisy, there’s more to it than mere volume.