In "Oh, the Innocents," the story of original sin has been updated and uprooted to that hotbed of temptation, the D.C. metro area. Paradise is now, it seems, a one-bedroom flat in a funky part of the city, and the Tree of Knowledge has been transplanted to leafy, iniquitous Potomac.

All those serpentine suburbanites, itching to corrupt the young bohemians of the city! Ari Roth's play, which is being staged by the company he runs, Theater J, is a modern morality tale with music that traces the parallel falls from grace of Jeremy (Peter Wylie) and Betsy (Liz Mamana), a songwriter and a singer whose marriage is tested by the manipulations of Alex (Lucy Newman-Williams), a sex-starved Potomac matron, and Zev (Dan Via), a predatory record producer.

That Jeremy and Betsy's union grows a little frosty is apt, because the production, directed by the author, proceeds at a glacial pace. Roth's ultra-slim thesis takes a luxurious 150 minutes to play out. It's as if a 60-second commercial had been turned into a six-part series.

Roth has demonstrated in previous pieces a fine ear for urbane chatter, but in the overwritten "Oh, the Innocents" the characters are deadeningly page-bound. In the work's promising opening scenes, the dramatist drops broad hints that Jeremy, who pays visits to Alex's spotless McMansion to teach piano to her jaded daughter Laurel (Lindsay Spencer), is to play Dustin Hoffman to Alex's Anne Bancroft.

Hope for "Graduate"-level satire fades, however, as the story circles around and around the rather dreary and dainty indiscretions of the central couple. In bed, Jeremy and Betsy engage in purple discussions about the clash between their bourgeois fantasies and their utopian values, a dream built around their gooey desire "to make this home holy with music -- our music."

As the tale's forlorn Beltway Siren, the wasted Newman-Williams is saddled with a series of transparently suggestive tasks, like asking for the young man's help in zipping up her dress and uttering breathless lines that conjure memories of Barbara Stanwyck in "The Thorn Birds": "Would you ever kiss me, Jeremy, for a very long time?" This being an equal opportunity conveyance for longing, Betsy has an ardent admirer, too -- Jeremy's best friend, Josh (Eric Sutton), a young investment banker who's more of a magnet for money than for chicks.

The feeling of overindulgence extends to the original music, which is used in confusing ways in "Oh, the Innocents." Roth's interchangeable songs (all composed in the same sluggish tempo) are at times set realistically in the clubs where Betsy performs, and at others are expressionistic devices, inserted as if they were numbers in a conventional musical. The songs are too sporadic to form a coherent motif and so remain oddly detached from plot and character. No convincing rationale is offered for the awkward segues into moody song fragments and ensemble numbers -- why, for instance, Zev materializes to sing a few plaintive bars in the couple's bedroom.

Wylie and Mamana capably project the angst and idealism Roth is after, though the notion that Betsy's lethargic repertoire would catch the ear of the recording industry takes a very large leap of the imagination. Sutton brings neurotic verve and a surfeit of charm to his assignment. Via has a nice singing voice, but he seems miscast as an emissary from a world of vice. I must note the awkwardness in evaluating this increasingly prominent performer, as Via is also a regular freelance contributor to The Post's theater coverage.

Daniel Conway's sliding-panel set and Steve McWilliams's guitar accompaniment are noteworthy technical elements, but the play they embroider needs substantial renovation. Roth, whose adventurous company routinely takes on risk, could perhaps have benefited from a director with more distance from the material. The one he chose seems not to have been helped by his lifelong association with the playwright.

Oh, the Innocents, written and directed by Ari Roth. Set, Daniel Conway; lighting, Jason Arnold; costumes, Susan Chiang; sound, Matt Rowe; musical direction, Steve McWilliams. Approximately 2 hours 30 minutes. Through Aug. 1 at DC Jewish Community Center's Goldman Theater. Call 800-494-8497 or visit www.boxofficetickets.com.

Jeremy (Peter Wylie) and Laurel (Lindsay Spencer) in Ari Roth's overwritten modern morality tale of original sin set in the District.