From the start of The Blue Room, with its shots of wrinkled sheets in a recently vacated hotel room, it's evident that Mathieu Amalric's film will focus not strictly on the illicit affair between Julien (Amalric) and Esther (Stéphanie Cléau) but on the aftereffects of unfaithfulness and center not on seduction but on the consequences of seducing and being seduced.

In such a scenario, the trope of the mad mistress casts a long shadow — think Fatal Attraction— as does that of the jealous, vengeful partner, who isn't hard to find either in today's theaters. Lying in bed, Esther repeatedly asks Julien variations on the question: "Could you spend your whole life with me?" So when she later begins sending him cryptic letters about their future together, you wonder whether a dead rabbit isn't too far in the future.

Esther's obsessive qualities are really only hinted at, though, as is the jealousy of Julien's wife, Delphine (Léa Drucker), which we suspect, in retrospect, only because another character asks Julien about it. Both are expectations, assumptions that Amalric and Cléau, who together adapted the script from Georges Simenon's novel, coyly dance around but never outright confirm or dismiss. Instead, they allow the audience to slowly realize just how much the events in The Blue Room are filtered through Julien's experience, and then to understand that his perspective might be crucially flawed.

Julien is presented emphatically as a small man — looking plain and diminutive standing next to the tall and elegant Esther. And with every turn in the plot, every new threat that his secret will be exposed, he shrinks more, his face an increasingly pitiful mix of helplessness and anguish. He's not an unreliable narrator, but because his demeanor is so pathetic, so seemingly harmless, our focus shifts to the events around him and to the growing sense of some unfortunate event certain to befall him.

Amalric helps us be carried in that direction, of course, using Grégoire Hetzel's score to evoke Hitchcockian thrillers and ratcheting up anticipation of a big reveal with a plot that is as much a legal thriller as it is the story of a torrid affair. The Blue Room's narrative jumps across time, flitting from the initiation of Julien and Esther's affair to its direct aftermath to Julien's testimony months later about an unspecified crime of which he is being accused.

The Blue Room pieces together the details of its plot like a jigsaw puzzle, but seeing the final picture is not its principal pleasure. Instead, if for the first half you're awaiting answers about what transpired between Delphine, Esther and Julien, much of what keeps the film compelling in its second hour is how revelations of small details shift the meaning of previous words and actions: What seemed like thoughtless pillow talk turns into criminal intentions; what seemed like unremarkable marital tension turns into dark premonitions.

The cumulative effect, though, is intriguingly anti-climactic. The Blue Room ends on a decisive note, but the film doesn't seem convinced of its own firm conclusion. One of the most striking qualities of the film is how little we really ever find out about Julien, or about the whole plot that has unraveled before us. As the credits roll, you may not be surprised at where you've ended up, but trying to look back at how you got there may make the path suddenly seem foggy. Amalric and Cléau are more than competent guides through the confusion, largely because they don't throw us into it immediately but guide us in using our own expectations, beginning a process of recalibration that's engrossing if not strictly illuminating.

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