About halfway through Jon Robin Baitz’s “The Paris Letter,” you start to realize that you’ve been issued a junk bond. It takes a while to get to that point, to realize the investment of time and ticket price have mostly gone to waste, because of some conspicuous dramaturgical razzle and some exciting casting dazzle. But at the intermission, as hordes of well-tanned, shiny-tied audience members gobble Rice Krispies Treats in the lobby, one has serious trouble dredging up the urge to return.

If you do flee, rest assured that the second half, telegraphed loudly by the first half, does not deviate at all from the expected. As a kind of nod to drama, one murder and one Hallmark style encounter with cancer do try to enliven (if that’s the right word) the second act. But as he did in “Ten Unknowns,” Mr. Baitz snags his gorgeous, complicated characters in a muddy plot, overworking their inner struggles until they are ground to mush.

Ron Rifkin, his muse and close friend, again turns out a slippery portrayal of self-delusion and success, and John Glover spins straw into gold as a narrator with “flair.” But, not unlike two of the central characters, the piece tries to force a marriage between genres that simply will not fit. The show’s daring premise, that coming out of the closet will not guarantee a happy life, could sustain a play of half its length. The rest, sadly, feels like badly appliqued patches from movies we all saw in the ’80s.

The play begins with a tale of darkest greed and corruption, spiced with sex and celebrity that borrows heavily from the Dana Giacchetto affair. Just like Giacchetto, the real-life broker who went to jail for defrauding Phish and Leonardo DiCaprio out of millions, Burt Sarris (Jason Butler Harner) has made some very illegal mistakes. In a shocking opening scene that actually had one audience member shout out for “Jesus Christ!” we see the boy-investor pay rather bloodily for those errors. His lover and mentor, Sandy Sonenberg (Ron Rifkin) walks away into the dark – and the action stops. Dead. For hours.

A narrator emerges: Sandy’s longtime friend and onetime lover, Anton (John Glover), wants to tell us Sandy’s story. In flashbacks to 2001, we meet Sandy, his wife, Katie (Michele Pawk); and his stepson – a happy bunch who gather in Katie’s restaurant to eat pasta with friends and talk. Paeans to the good life alert us to a coming fall, and when Sandy asks Anton about the new guy at the table, Burt, we know Sandy’s happy homelife has a canker.

Mr. Baitz dodges the usual patterns of sexual-repression tales; his Sandy has been frank with his wife about his past. Pushing our credulity to a desperate point, Sandy’s choice to turn his back on his homosexuality has been deliberately pursued over decades with the help of a psychiatrist (also played by Mr. Rifkin). But Sandy’s affair with Burt has awful consequences, not because of his years of self-deception, but because he lets his lover take over his treasured investors. The real lesson here? Repress all you like, but brokers make lousy boyfriends.

Pursuing Sandy’s pathology ever backward, Mr. Baitz then sends us to 1962, for a long and chemistry-free series of scenes between the just-out Sandy (Daniel Eric Gold) and young Anton (Jason Butler Harner again). Mr. Gold has more spark with his mother (played lusciously by Ms. Pawk) than with the floppy, affected Mr. Harner, and the show’s one chance to depict honest love goes to waste.

Lots and lots of talk about love can’t quite convince us of many of the central relationships. Conviviality, something the characters and Mr. Baitz understand very well, spills out of the dinner scenes in great, generous waves, and much is made of New Yorkers’ obsession with food and conversation. But love and lust, the two whips that should drive this play, never lay their lash to our backs. And as for the early promise of the piece, that we would get a nasty, no-holds-barred expose of financial malfeasance? It disappears into the background, never to reappear.

Director Doug Hughes and designer John Lee Beatty, the team that brought us “Doubt,” use the same gliding delivery as in their more successful collaboration. Everything is handsome, everything moves smoothly. The preview I attended was so overrun by the starry audience, we plebians had to throw elbows at Sarah Jessica Parker just to find our seats. But while the presence of TV notables would normally signify “stunt” casting, this cast works as seamlessly as one of Mr. Beatty’s sliding tables. Messrs. Rifkin and Glover remind us of how gracefully actors can negotiate a multimedia career, how marvelous it is when occasionally Hollywood can feed the actors who feed us.

Until August 7 (111 W. 46th Street, between Sixth and Seventh Avenues, 212-719-1300).