“Lust, Caution” is a film noir that’s too small for its britches: it may be cloaked in the finest material, but it is also drowning beneath the folds.

While audiences will be captivated by the film’s languid, shadowy images and tortured characters, the overall effect is diluted by excessive length (158 minutes) and lack of development. Taiwanese director Ang Lee, known for “Brokeback Mountain” and “Crouching Tiger, Hidden Dragon,” adapts Chinese author Eileen Chang’s eponymous short story with exquisite artistic balance, but the film’s visual density simply cannot compensate for its paucity elsewhere.

Set in Japanese-occupied Shanghai and Hong Kong during World War II, the film spans the four-year attempt of a Chinese student drama group to assassinate a top Japanese collaborator, Mr. Yee (Asian cinema icon Tony Leung), using virginal Wong Jiazhi (newcomer Tang Wei) as a lure. Wong poses as a well-bred aristocratic wife, Ms. Mak, and employs her acting abilities and womanly wiles to delicately tempt Mr. Yee. Taming the beast, however, becomes an increasingly perilous and poisonous endeavor.

The character dynamics are evocative and rich in nuance. They comprise the film’s nucleus and are roughly microcosmic of the external political conflict. The first half of the movie underscores the students’ naïve confusion between histrionic ideals and a harsher reality, until a particularly bloody episode jars the troupe and shows that they have already committed themselves to the latter.

Unfortunately, this commitment proves an indelible action. The relationship between Wong and Mr. Yee absorbs the two until it is impossible to distinguish performance from truth. Initially, Wong, an inexperienced schoolgirl, channels a darker side solely for her unfolding professional life. Yee, conversely, a man known for his animalistic brutality, bares a worn, solitary countenance behind closed doors.

These two dichotomous characters unwittingly create a relationship that assumes a dual nature in itself: restrained and unbridled, violent and erotic, lustful and odious. These dualities grow inextricably intertwined through intimacy, portrayed in a series of graphic sex scenes. Though these scenes are clearly responsible for the film’s NC-17 rating, the bedtime power plays expose the relationship’s ability to consume and transform the pair.

Unfortunately, the evolution of this relationship is about as far as the film goes. Exhibited largely through a combination of stolen glances and acrobatic bedroom activity, the dynamics ultimately turn repetitive.

Additionally, Wong’s character development is lacking. While Wei’s acting is exquisite, the script, co-written by Focus Features favorite James Schamus, fails to make believable her transition from schoolgirl to femme fatale.

In an Associated Press article, Lee recognized that American audiences—and box offices—might not react well to the NC-17 rating and subtitles. “Its pace, its film language —it’s all very Chinese...It’s not very audience-friendly for a market like the U.S. It’s not their subject matter,” he said.

But despite low expectations, the film has garnered successes, notably a Golden Lion Award at the Venice Film Festival, where it premiered. And since its debut in New York, the film has been highly profitable, particularly for a foreign-language film.

“Lust, Caution” faces an uncertain future in America. A mature audience willing to bear with a drowsy pace may appreciate the glamorous visuals and seductive draw. The film is sobering and dark, simple at its core. But stretched over two and a half hours, even its rich meaning wanes.

—Staff writer Erin F. Riley can be reached at eriley@fas.harvard.edu.