The intersection of mystery and epistemology can be a lively place to set a film, as Alain Resnais and his many imitators have demonstrated. The Whodunit? agenda of the standard Agatha Christie–style yarn becomes the much more complex Did someone do something? And, if so, how do we know? That’s a gambit that would naturally appeal to writer-director Atom Egoyan, who prefers that his movies (among them The Sweet Hereafter and Ararat) unpeel like an onion. It also hooked Marc Forster, who after following Monster’s Ball with Finding Neverland is clearly intent on not doing the same thing twice. Alas, both filmmakers’ latest efforts ultimately yield to routine explications. Before they deflate into mere intrigues, however, Egoyan’s Where the Truth Lies and Forster’s Stay scramble reality with agreeable gusto.

An accidental companion piece to Capote—and to Jerry Lewis’ new memoir—Where the Truth Lies is another inquiry into celebrity and corruption in pre-HBO America. Watergate is about to sully the country’s innocence when young reporter Karen O’Connor (Alison Lohman) begins to probe the untold story of former song-and-joke partners Lanny Morris (Kevin Bacon) and Vince Collins (Colin Firth), whose similarity to Jerry Lewis and Dean Martin is no fluke. But the suppressed scandal at the heart of their story happened back when Eisenhower was president and Lanny and Vince were conducting telethons to battle polio. In those days, the after-show party could get wild, but what happened backstage stayed backstage. So it’s never been revealed just how that beautiful blond corpse appeared in Lanny and Vince’s suite in a mob-controlled New Jersey hotel, shortly before the two men ended their partnership.

Adapted from a novel by Rupert Holmes—yes, the piña-colada guy—Where the Truth Lies could have been an ordinary murder mystery punctuated by a few yearning sighs for lost showbiz glamour. Yet Holmes’ scenario includes elements that mirror Egoyan’s long-standing concerns, notably baroque sex (Exotica) and surveillance (Family Viewing). Lanny and Vince take drugs and whichever women they want, including Karen and the victim, Maureen O’Flaherty (Rachel Blanchard), another aspiring reporter. Maureen’s death occurs in the ’50s, so there’s no video, but there is an audio recording with incriminating details. And 15 years later, during one of the movie’s fateful threesomes, photographs are taken. As so often in Egoyan films, titillation and blackmail are just two possible readings of the same image. (The sex is not explicit, but the kinky ambience was enough to draw an NC-17, which the distributor ducked by releasing the movie unrated.)

Gliding between 1957 and 1972 on cinematographer Paul Sarossy’s fluid camera movements, the director stuffs the film with subtext, associations, and asides. If Lanny and Vince are duality in action—a “boy-girl act,” as the former puts it—Karen is two women in one (or six in three). In addition to being the dead Maureen’s symbolic doppelgänger, Karen also appears in the film as a ’50s girl and ’70s woman, and briefly becomes Lanny’s lover while posing as her best friend, Bonnie. Egoyan conflates Lewis Carroll and David Lynch, arranging an L.A. orgy to the strains of “White Rabbit,” and stages the mystery’s breakthrough conversation on the streets of a Hollywood back lot, so as to assert the moment’s artificiality. The roles of clowning philanthropists, played in public by the secretly ruthless and self-serving Lanny and Vince, are hardly the only hollow edifices on display.

Compellingly balmy as some of this stuff is, Egoyan eventually accepts Holmes’ plot, which involves numerous affronts to history and common sense. The murder’s solution turns on fear of an exposé that never would have happened in the ’50s, when stars’ illicit idiosyncrasies were routinely concealed by the entertainment press. The story also involves frequent handling of the corpse—the effects of which would have caught the attention of any coroner, even one using ’50s technology—as well as a killer whose identity Ms. Christie herself might have rejected as hopelessly hackneyed.

Perhaps the picture would have been convincing with actors who played both sides of their characters with equal confidence, but Bacon and Firth are much more believable as offstage louts than as onstage charmers, and Lohman’s bland performance consists principally of wide-eyed looks and plunging necklines. Where the Truth Lies is a relatively big-budget, relatively mainstream project for the Canadian art-film director, and someone or something induced him to cast bankable stars—such Egoyan stock players as Don McKellar and Arsinée Khanjian have only cameos—and offer a tidy resolution. It’s the movie’s messy parts, however, that fitfully fulfill the promise of Holmes’ jokey title.

An immaculately art-directed plunge into bewilderment, Stay begins with a disorienting car crash that recalls the opening of Krzysztof Kieslowski’s Blue. The survivor of the collision, whose name we’ll later learn is Henry Letham (Ryan Gosling), walks toward the camera, and his face suddenly becomes that of Sam Foster (Ewan McGregor)—another doppelgänger, and not just for Henry. Given the similar surnames, Foster may also be a surrogate for director Marc Forster.

On one level, the relationship between the movie’s two principal characters is simple. Henry, despondent after the crash, meets Foster, a psychiatrist who takes him as a patient because the brooding art student’s regular shrink (a briefly encountered Janeane Garofalo) has had a nervous breakdown. In his shortish trousers and longish neo-Edwardian jackets, Foster looks a bit silly, but he’s quite serious about Henry’s announced suicide plans. The doctor’s vivacious girlfriend (Naomi Watts), a painter who happens to teach art at the Manhattan university where Henry studies it, has nasty scars on her wrists, a constant reminder to Sam that some people don’t just talk about killing themselves.

Henry is melancholic and ethereal, with an empty gaze so haunting that it repeatedly summons the Guess Who’s “These Eyes” (although something by the Cure would have been more appropriate). The aspiring painter and determined nihilist has set a date for his death, his 21st birthday, which is just three days away. After a few scenes that explain why Sam can’t simply turn Henry’s case over the authorities, the impassioned shrink becomes a full-time sleuth, searching for clues to Henry’s disposition and plans. Sam’s quest doesn’t lead to orderly exposition, however, but to increasingly subjective and surrealistic perceptions. Camera angles turn oblique, time shifts and stutters, simple doors become teleportation portals, and everyday interiors are rendered strange and ominous.

“Tell me what the truth is,” Sam demands, and Stay eventually does. The disclosure is, of course, a disappointment, encompassing tricks from the repertoire of The Twilight Zone, M. Night Shyamalan, and The Wizard of Oz. Still, as an evocation of madness the film is a lot more effective than In Her Shoes or Proof, two recent movies that summon the specter of inherited schizophrenia only to wriggle away from it. Stay is a jaunty dislocation dance that’s not entirely undercut by the banal conclusion of David Benioff’s script.

Forster uses lots of special effects, yet Stay recalls Resnais’ Last Year at Marienbad, which conjured a profound sense of alienation by using only razor-edge editing and striking locations. As he demonstrated with the Spike Lee–directed 25th Hour, Benioff has a thing for dream visions of New York, and this movie sends its characters through a series of actual atriums, corridors, and staircases that blur the boundary between industrial chic and nightmare backdrop. At a time when every other American director seems to be going for the exact same shot of the Manhattan skyline or the Hollywood hills, Stay shows us places we’ve never seen before. And that’s an experience that very nearly justifies the film’s prosaic payoff. CP