If you like the groovy movie poster for American Swing, I suggest you buy it and save yourself the price of admission. The enticing imagery, reminiscent of some of my own recent-favorite ’70s lifestyle entertainment offerings — an homage film called Viva and the unfortunately canceled TV series Swingtown — is little like the documentary it advertises. The poster is intriguing, sassy, funny, and up-tempo, while the movie is plodding, drab, and completely humorless (save for the last word, courtesy of prolific porn star Fred Lincoln, which is priceless. Think: Larry Clark’s Kids).

American Swing, running too long at 80 minutes, is a flavorless, meandering overview of the rise and fall of Plato’s Retreat, a very popular New York City public sex club that opened for business in 1977 and then, due to greed, stupidity, mismanagement and, of course, the advent of AIDS, closed its doors forever in the mid-’80s.

Plato’s Retreat was the brainchild (though he was probably thinking with the other head) of Larry Levenson, a stereotypical gold chain-wearing, graceless Brooklyn satyr seizing on the zeitgeist of the libertine disco-era airheads whose vocabulary basically consisted of phrases like “key party,” “suburban roulette,” “open marriage,” “swinging” and “lasagna buffet.”

Don’t get me wrong — I love the ’70s and have enjoyed some incredible documentaries on the decade-long bacchanal…but mostly they’re from television (VH-1’s Behind the Music on Studio 54 is a standout, as are some of the programs on The History Channel and E!). That medium lends itself to a more succinct storytelling style, while the big-screen American Swing just goes on and on with no narrative structure. Unbridled and clearly unguided, the interviewees — ranging from Retreat employees to patrons to minor celebrities — blather on endlessly.

The doc does, in its favor, offer up original hit songs from the era, as well as lots of photos and footage taken inside the basement-bound club (of the Ansonia Hotel on the Upper West Side) which clearly had no “velvet rope” policy. It would appear that every schlub and his soccer-mom wife were admitted and, in the beginning, it was just about the party and the sexual availability of its mostly married patrons.

As one imagines, the hot-tubs began to resemble cottage cheese factories and the orgy rooms took on a crusty patina — the jaded customers demanded more. Live sex shows were added, including bondage, bloody S&M, and…er, “pony rides.” (Don’t even get me started on “kid’s night”!) We see a few familiar faces reminiscing (Ron Jeremy, Donna Ferrato, Al Goldstein, Annie Sprinkle, and Melvin Van Peebles, to name a few), but it’s mostly an assembly line of dull, long-winded talking heads whose names are quickly forgotten.

The good times could only roll for so long, though. In spite of his celebrity status and many television appearances (clip from the Phil Donohue Show are a worthy curio), Levenson’s girlfriend Mary (who was a central figure in the story but whose last name is never revealed) left him for someone else and then had a nervous breakdown; he was badly beaten by strangers and was hospitalized; got in trouble with the IRS; went to jail; and finally had to shut Plato’s Retreat down for good after the AIDS ravage. All of this is presented in a casual, blasé point-A-to-point-B manner.

I wish I could accuse the film of being a whitewash, but it doesn’t even take that much of a stand: American Swing isn’t nearly as nostalgic or affectionate as it could be, nor is it cautionary, investigative or informative, so I really don’t understand the reason for its being.

There’s a lot of drama and intrigue inherent to the story of Larry Levenson and his ground-breaking sex club, but this poorly directed, aimlessly edited, flaccid mess definitely can’t get it up.

Opens in Los Angeles on April 3, 2009.