Very soon after the start of David Mamet's "Edmond," the title character, a 34-year New York businessman, walks out on his wife. At the end of this 75-minute intermissionless drama, he is in prison, tentatively embracing the black cellmate who has sodomized him.

In between, there are a few dozen staccato scenes, as Edmond dips deeper and deeper into the sleazy life of the big city. Clip joints, B-girls, street-corner card sharks, peep shows, pimps, massage parlors, muggers -- he encounters them all in what Mamet sees as a spiritual odyssey into the heart of darkness, but what may strike others as just plain slumming.

In the subway, Edmond tells a woman she is wearing a hat like one his mother had. She recoils. He explodes with Goetz-like fury. In a coffee shop, he picks up a waitress with ambitions of being an actress. They go back to her place for a romp. He pushes her to admit that she's really nothing more than a waitress. She gets edgy. He stabs her to death. Onward and downward into the lower depths.

It's a frank and brutal world that the Paradise Island Express has recreated on the stage of the GALA Theatre in the Lansburgh Cultural Center. But if the production, directed with dank sobriety by Deirdre Lavrakas, commands attention, the play itself verges perpetually on parody. Mamet has a keen ear for the clipped and jittery speech of the inarticulate, but he's hearing more than gritty mutterings this time. Grand pronouncements about predestination, loneliness, God and the void keep intruding in this netherland and they bear a distressing resemblance to the platitudes of a late-night college bull session.

"Every fear hides a wish, don't you think?" Edmond says to his cellmate. Apparently, Mamet considers Edmond's plunge from a conventionally boxed-in existence into chaos as a kind of liberation. All Edmond's fears -- about women, blacks, homosexuals, violence, degradation -- come true. But he is at last himself, presumably at peace for having acknowledged the goblins within. This is not the Mamet of the taut "Glengarry Glen Ross." It is, alas, the Mamet who wrote the philosophically bloated "The Woods."

The Paradise Island Express production gives the work more than an even break. The fragmented set, bits and pieces of the city spilled over the stage, is appropriate, and Kim Peter Kovac's lighting -- dingy whites, poisonous greens and steely blues -- is even more so. Most of the roles are no bigger than cameos, fleeting phantoms in the nightmare, but the Paradise Island Express cast etches them sharply and succinctly.

Dianne Couves finds surprising depth and poignance in the coffee shop waitress. Reginald Metcalf is eerily deceptive as a sweet-talking pimp who turns lethal. And you have to check your program to be sure that Pat Tulli, all brass and garters as a peep show performer, is also the grave fortune teller who informs Edmond that his fate is unavoidable.

As Edmond, Christopher Hurt projects a sullied innocence that helps counterbalance the character's unsavoriness. The problem, however, is not that Edmond is a vile creature, but rather that Mamet has left so many blanks for the actor to fill in. Hurt does his best -- with anger, suspicion, remorse, bewilderment. But the arc he must trace from the respectability of the Upper West Side to the ignominy of prison is a huge one. And Mamet hasn't provided much guidance -- only a series of rude buffets and vicious blows, masquerading as destiny.

Edmond, by David Mamet, directed by Deirdre Lavrakas. Set, Kate Guenther; lighting, Kim Peter Kovac; sound, Paul Lavrakas; fights staged by David Rothman. With Vince Brown, Dianne Couves, Christopher Hurt, Reginald Metcalf, Michael Morris, Pat Tulli. At the GALA Theatre in the Lansburgh Cultural Center through April 14