In “Stay,” director Marc Forster (“Monster's Ball”) conjures a striking gallery display of duality, identity and consciousness. If only he had something resembling a concrete plot to occupy his woefully murky main stage.

Admired for his visual wit and emotional bravery, Forster — Oscar-nominated for last year's “Finding Neverland” — loses himself somewhat in a dreamlike maze of twists, turns and psychological cul-de-sacs.

Dressed in an assortment of stylishly ill-fitting tweed suits, Ewan McGregor (“Big Fish”) plays Dr. Sam Foster, a New York City psychiatrist whose very sense of reality begins to unravel when he treats Henry Letham (Ryan Gosling from “The Notebook”), a suicidal young artist who hears voices and believes he murdered his parents, despite evidence to the contrary.

From the outset, the director makes it apparent — a bit too apparent, perhaps — that Sam and Henry share some strange, metaphysical connection. At times, Henry seems to know exactly what Sam is going to say. Frequently, doctor and patient are glimpsed in the vicinity of identical twins and like-dressed people. And there's the suggestive way Forster uses digital morphing effects, blending one man into the other.

The upshot: Henry gets fully into the doctor's head, an arrangement that aggravates Sam's never-quite-dormant concern for his live-in girlfriend (Naomi Watts, mostly ornamental), herself a suicide survivor who also happens to be an artist.

Suffice to say, matters only get weirder and more feverishly surreal for Sam, who intermittently finds himself trapped in inverted, looping stairwells and other M.C. Escher-inspired geometric implausibles.

Forster's reality-bending onslaught makes for a good show — servicing the idea that Sam and Henry comprise some sort of one-sided human Möbius strip — but there's a hefty downside: Never once do we suppose that the story takes place anywhere but in somebody's disoriented psyche, a la “Jacob's Ladder.” A puzzle without dimensions really isn't a puzzle, leaving us to simply await the big twist ending when it all finally comes into focus.

And even that proves to be a letdown. At best, “Stay” is a statement about the elaborate fictions that the human mind can create in its most desperate, traumatized moments.

‘Stay’
Starring: Ewan McGregor, Ryan Gosling, Naomi Watts, Bob Hoskins
Rating: R (profanity and some disturbing images) Running time: 99 minutes
Playing: Opens Friday in theaters Valleywide
GRADE: C+