The camera races after Mamie (Lisa Kudrow), who runs, hysterical, through a rough patch of woods, her image jagged by the handheld cinematography. She reaches a clearing, rushes into the street, and is violently slammed by an oncoming car. It’s a nasty shock; the audience gasps. Then a title card slips in from the right, splitting the image into two panels. “She’s not dead,” it reads. Another: “No one dies in this movie. At least onscreen. It’s a comedy.” After twisting through a great deal of structural caprice, “Happy Endings” will, in the end, loop back to explain this scene. It’s ever so clever like that.

Best known as the writer-director of “The Opposite of Sex,” Don Roos is back with his contribution to the most spurious of contemporary subgenres: the postmodern indie dramedy. You know the deal: A hipster ensemble must negotiate narrative contrivance as they grapple with the conundrums of modern identity. What’s it all about? “Love is the prime motivating factor for everyone in the film,” Mr. Roos says in the press notes. “It’s true in my life, so I assume it’s true in everybody’s life. That’s the kind of ego I have. If it’s true for me, it’s true for you.”

The movie is set, needless to say, in Los Angeles.

As a teenager Mamie screwed her foxy stepbrother, got pregnant, and aborted the fetus. She grew up to be an abortion counselor. (Naming this character “Mamie” obliterates the line between clever and stupid.) Charley (Steve Coogan), the stepbrother, turned out neurotic and gay (title card: “Who isn’t these days?”). He now runs a restaurant, and is partnered with Gil (David Sutcliffe), a confident, successful architect. Gil is best friends with Pam (Laura Dern) and Diane (Sarah Clarke), a lesbian couple raising a child who may or may not have been co-created with Gil’s sperm.

See, he donated some a couple years back, but it didn’t take, at least according to the moms. Charley suspects they’re lying, and in an effort to provoke a confession out of them, in vents an outrageous story about Gil’s sudden affliction with a terminal, hereditary brain disorder. Asking us to swallow these faux-farce shenanigans is the least of the movie’s problems. But, then, plausibility is so reactionary, don’t you think?

Meanwhile, we find out Mamie didn’t abort her kid, but secretly gave him up for adoption. Enter the supremely vulgar Nicky (Jesse Bradford), an obnoxious aspiring filmmaker who claims to have tracked down her orphaned offspring then blackmails her into helping him make a documentary – about the effort to find her child. Through a series of events far too ridiculous to describe here, they embark instead on a docudrama about Mamie’s boyfriend Javier (Bobby Cannavale), a Mexican immigrant employed as massage therapist.

Back at Charley’s restaurant, Otis (Jason Ritter), a 22-year-old closet case, meets Jude (Maggie Gyllenhaal), a mercenary hottie. After a round of karaoke, Jude agrees to sing vocals in his band, Serpentine. She quickly seduces him, and just as quickly rebuffs him with a load of “fag” quips. Jude, gold-digging, gloms on to Frank (Tom Arnold), Otis’s wealthy father. There are a couple hundred other plot twists I’ll spare you. The important thing to know is that each of these off-the-wall stories intersects in various “droll,” “ironic,” and “unexpectedly moving” ways.

At 130 minutes – a brutal runtime for comedy – “Happy Endings” somehow manages not to be insufferable. Deftly acted and briskly paced, Mr. Roos’s torrent of manipulative falsehoods is an enjoyable enough way to while an afternoon so long as you call its bluff. But then maybe what’s true for Mr. Roos will seem true to others. After all, people took the claptrap in “Crash” seriously.

Perhaps there are rich L.A. hipsters with cool, art-collecting dads who are still in the closet at 22. Maybe some otherwise reasonable man would, in a crazy plot to validate his paranoid theories, sabotage his lover’s closest friendship by pretending his brain was turning to mush. Who knows? That L.A. sure is once crazy place!

An extremely self-conscious filmmaker, Mr. Roos surely understands his touch tweaks realism. Were the movie funnier, the contrivances might pay off. And were the angsty Angelinos of “Happy Endings” more credible, the movie’s cathartic ambitions might not ring so hollow. Nevertheless, I’ve got to give him this: The man can cast. Saddled with a heap of lies, his players fly.

Forget Bill Murray; Ms. Kudrow is the most talented self-deprecator in the business. Ms. Gyllenhaal does the sassy gamine beautifully. And who would have suspected Mr. Arnold capable of such affecting vulnerability? True to his name, Frank is the film’s lone repository of truth. Otherwise, “Happy Endings” is endless hokum.

***

How fortuitous that “The Reception” is getting a theatrical release; this humble, small-scale, micro-budgeted movie is the richest American indie I’ve seen this year. How appropriate that it opens today; its tough-minded complexity rebukes the flip pseudo-sophistication of “Happy Endings.”

Jeannette (Pamela Holden Stewart), a volatile Frenchwoman, has taken Martin (Wayne Lamont Sims), an introspective painter, under her wing. She drinks too much; he doesn’t do much of anything. They live quietly together in Jeannette’s large, bright, plainly appointed country home. One snowy afternoon, Jeannette’s estranged daughter Sierra (Margaret Burkwit) shows up with her new husband Andrew (Darien Sills-Evans).

What follows, as in “Happy Endings,” is a series of deceptions, revelations, confrontations, and denouements, as each of these characters is forced to address the lies they’ve told each other and themselves. Sierra’s motives are not what they seem – nor is her “husband.” The tension between Martin (a handsome gay black man) and Andrew (a handsome straight black man?) is palpable from the beginning. Anxieties implicit in Jeannette and Martin’s platonic codependency are pushed to the surface. Love – and fear of love – is the prime motivating factor for everyone in the film.

Writer-director John G. Young is interested in much the same territory as Mr. Roos; “The Reception” pulls taught many of the same sexual knots and emotional tangles as “Happy Endings.” Less of a smarty-pants but twice as smart, Mr. Young adds an exceptionally delicate, clear-eyed empathy for the class and racial tensions that simmer, unacknowledged, within polite liberal society. Both films are contrived; but where the structural shenanigans of “Happy Endings” are applied from the outside in, the rapid-fire revelations in “The Reception” are precisely keyed to interior developments. There’s something legitimately at stake here.

“The Reception” depends for all its effects on the acting and writing (the digital videography is undistinguished but unobtrusive). With the exception of Ms. Burkwit, unconvincing in an underwritten role, the cast is superb. Ms. Stewart is charming, imposing, delicate, and intense – a riveting performance. Messrs. Sims and Sills-Evans reach for their notes and sound them with restraint. There’s not an overplayed moment in this careful little gem.