Ordinarily, the news that Kevin Bacon and Colin Firth have a menage a trois in a movie should be enough to send the curious running to the art house. But not when the movie is ''Where the Truth Lies."
The film gives us Bacon and an intense Firth as Lanny Morris and Vince Collins, a 1950s comedy duo -- like Martin and Lewis, only sweatier and with less chemistry. Every Veterans Day, they host a tear-jerking, knee-slapping polio telethon that the nation loves. One night, after a show, the corpse of the pretty girl they had sex with the night before turns up in their hotel suite. They're never charged with anything, but their good names are dragged through the tabloids for years.
A decade and a half later, in the early 1970s, someone starts digging through the case again. Her name is Karen O'Connor, she's played by Alison Lohman, and, in a narration that never seems to end, Karen gives us her pitch. ''I was a young journalist with a desperate need to prove myself," she says. She's not the only one.
''Where the Truth Lies" is an erotic thriller. It is also an Atom Egoyan picture, which means any claims either to actual eroticism or conventional thrills are theoretical at best. Egoyan often takes a natural movie genre (the weepie melodrama or the historical epic, say) and pumps it so full of intellect it mutates into something unrecognizable. This ambition to dismantle has produced some masterstrokes (1998's ''The Sweet Hereafter") and some misfortunes (''Ararat," his previous film).
''Where the Truth Lies" is too smart for its own good. Karen arrives in this sunny Hollywood morass determined to unearth what really happened that night for her book. She tracks down Vince and Lanny, who haven't spoken to each other in ages. Between them, we're given enough information to take us back 15 years to that hotel room, where their menage a trois went murderously awry.
Each man has his own stipulations, and Karen proves adept at the cagey maneuvers required to get what she wants. This girl makes Truman Capote look like Edward R. Murrow. Karen doesn't stop at lying. To please Vince, Karen fools around, in the film's most heavy-handed metaphor, with a girl who stars in a trippy kiddie musical version of ''Alice in Wonderland." Egoyan shoots the sequence as a soft-core fantasy, one that, given the nature of the film's big mystery, suggests that the director's entire enterprise is built on a nonnegotiable double standard.
But the real problem is that Egoyan tries to use allusions and self-awareness to class up the smut he's peddling. Characteristically, he wants us to play detective and question the nature of truth in life and in art, which is fine. The trouble with ''Where the Truth Lies" is that it's lousy art. Egoyan rubs our noses in behavior that he seems to think his movie is too good for. This could hardly be what Rupert Holmes had in mind when he wrote the addictive and fearlessly rude potboiler that the movie's based on. Holmes is also the composer of ''Escape (The Pina Colada Song)," so presumably when he writes about a decadent, erotic interlude, unlike Egoyan, he means it.
Wesley Morris can be reached at email@example.com.