"The Oh in Ohio" is a frank, if somewhat implausible, indie comedy about a topic—sexual dysfunction—not often explored on film. Directed by Billy Kent and written by Adam Wierzbianski (both making their respective feature debuts), the picture whips up a charming, airy tone even as it goes overboard in slapstick sequences that don't always fit in with its character-based story. The actors are game—Parker Posey (2006's "Superman Returns") is especially lovely in a too-rare lead role—but they can only do so much with a script that unevenly jumps between two separate storylines and often seems to be discarding crucial chunks of the characters' personal journeys toward self-discovery.

Even as Cleveland native Priscilla (Parker Posey) is excelling at her city advertising job, she is failing miserably in her marriage to high school science teacher Jack (Paul Rudd). The cause of their friction? Priscilla has never had an orgasm. Soon Jack has moved into the garage, and later into his own apartment, rediscovering along the way the reciprocal joy that can come with sex when he begins dating teenage student Kristen (Mischa Barton). Meanwhile, in a major step toward getting over her sexual hang-ups, Priscilla purchases a vibrator. While orgasming suddenly comes very easy to her—having never masturbated before, she quickly becomes addicted—Priscilla begins to learn that her frigidity has little to do with the physical act of sex and everything to do with her fear of intimacy within a relationship.

To put it mildly, "The Oh in Ohio" lacks focus. The first and lesser half simultaneously follows the paths Priscilla's and Jack's individual lives take once their marriage hits the rocks. While Jack starts getting into shape and begins secretly hooking up with Kristen, an outgoing high school student more than comfortable with her body, Priscilla's life becomes overrun by her sudden need to reach orgasm through anything that vibrates—including her cell phone. The scenes between Jack and Kristen aren't developed enough to be believable, and are a little disturbing in the way he holds no qualms about having sex with a possibly underage student. Priscilla's interludes with chronic masturbation are over-the-top to the point of being as juvenile as a raunchy high school sex comedy.

And then, suddenly, director Billy Kent establishes his footing. Jack and his relationship with Kristen is all but forgotten—they disappear for at least a solid thirty-minute block—and Priscilla's journey toward fulfillment that doesn't involve mechanical objects takes over. After a series of unsatisfying sexual encounters, including a disastrous lesbian experience with a sex shop employee (Heather Graham), Priscilla finds herself falling for an unlikely possible mate in pool company owner Wayne (Danny DeVito). Wayne is older, shorter and rounder than Priscilla, but she refreshingly doesn't seem to notice, or care. They connect in a natural, effortless way that Priscilla never was able to with Jack—there is a wonderfully romantic scene between the two in which Wayne shows Priscilla the grandly designed backyard pool and water slide he built for his deceased wife—and the film pleasingly turns into a sweet and unconventional love story.

As the wide-eyed Priscilla, Parker Posey is at the heart of "The Oh in Ohio." She is such an inherently funny and, when given the chance, humane performer that she is able to work out a lot of the broad tonal kinks in the script. One can't help but sense that she is above some of the sillier material, as in an embarrassing rip-off of a scene from "When Harry Met Sally" where she orgasms in the middle of a business meeting, but she also proves that she has what it takes to be a firecracker of a romantic leading lady.

Paul Rudd (2005's "The 40-Year-Old Virgin") is given the short end of the stick as Jack; not only is his subplot undernourished, and his marriage to Priscilla only cursorily developed, but screenwriter Adam Wierzbianski forgets to give him a palpable arc in the third act. No fault of Rudd's, but Jack's scenes could have been cut out completely and would not be missed. As the catalysts for Priscilla's and Jack's sexual reawakenings, Danny DeVito (1998's "Living Out Loud") is a perfect against-type foil for Posey as the kind-natured Wayne, and Mischa Barton (1999's "The Sixth Sense") struggles to breathe life into the two-dimensional Kristen.

"The Oh in Ohio" is attractively and interestingly filmed on location in Cleveland—this city, not frequently seen in movies, is a character in itself—and is genuinely beguiling when the romance between Priscilla and Wayne takes shape. Unfortunately, this doesn't happen until about the forty-five minute mark, and there is a lot of frivolous filler to wade through in the interim. Director Billy Kent shows glimmers of filmmaking prowess, keeping the pace moving despite some jerky editing, and should be commended for moving the picture in a direction less predictable than most love stories. As a whole, though, "The Oh in Ohio" is narratively too bumpy a ride to be fully successful, its coarse opening sections ill-matched for the warmly compassionate tale it ultimately matures into.